Document and Entity Information Document Information [Table] Document Information [Line Items] Document and Entity Information Document Type Document Period End Date Entity Registrant Name Amendment Flag Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Central Index Key Statement of financial position [abstract] Non-current assets [abstract] Non-current assets Intangible assets other than goodwill Intangible assets Property, plant and equipment including right-of-use assets Property, plant and equipment Deferred tax assets Deferred tax assets Investments accounted for using equity method Carrying amount Investments accounted for using the equity method Other non-current assets Other non-current assets Other non-current assets Non-current assets Total non-current assets Non-current assets Current assets [abstract] Current assets Trade and other current receivables Trade receivables and others Current tax assets, current Tax receivables Tax receivables Other current assets Other current assets Other current assets Cash and cash equivalents Net cash and cash equivalents at the end of period Cash and cash equivalents at beginning of period Cash and cash equivalents Cash and cash equivalents Current assets Total current assets Current assets Assets Total assets Total assets Equity [abstract] Shareholders' equity Issued capital Share capital Share premium Premiums related to share capital A component of equity representing retained earnings excluding profit (loss) for the reporting period, and treasury shares Retained earnings excluding profit (loss) for the reporting period and treasury shares Reserves Reserve of exchange differences on translation Translation reserve Retained earnings, profit (loss) for reporting period Net loss for the period Equity Balance at the end Balance at the beginning Total Shareholders' equity Shareholders' equity Non-current portion of non-current borrowings and non-current lease liabilities Non-current portion of non-current borrowings and non-current lease liabilities Long-term debt Non-current derivative financial liabilities Long-term debt - derivatives Derivatives instruments The non-current portion of non-current royalty certificates issued. Non-current Portion of Non-current Royalty Certificates Issued Royalty certificates liabilities Non-current provisions for employee benefits Provisions for retirement benefit obligations Non-current contract liabilities Long-term contract liabilities Other non-current liabilities Other non-current liabilities Non-current liabilities Total non-current liabilities Current borrowings and current portion of non-current borrowings and current lease liabilities Current borrowings and current portion of non-current borrowings and current lease liabilities Short-term debt Other current provisions Closing balance Beginning balance Short-term provisions Current trade payables Trade payables Other current liabilities Other current liabilities Current liabilities Total current liabilities Current liabilities Liabilities Total liabilities Equity and liabilities Total liabilities and shareholders' equity Equity and liabilities Profit or loss [abstract] Revenue from contracts with customers Revenue Revenues The amount of other income from ordinary activities. Other income from ordinary activities Other income Total other income Revenue and other operating income Total revenues and other income Research and development expense Research and development costs Sales and marketing expense Marketing - Business development expenses General and administrative expense General and administrative expenses Other operating income (expense) Other operating income (expenses) Other operating income (loss) Profit (loss) from operating activities Operating profit (loss) Net operating loss Finance income Financial income Total financial income Finance costs Financial expenses Total financial expenses Finance income (cost) Net financial income Financial income (loss) The entity's share of the profit (loss) and dilution gain (loss) of associates accounted for using the equity method. Share Of Profit (Loss) and Dilution Gain (Loss) Of Associates Accounted For Using Equity Method Share of net loss (Equity method) and dilution gain Tax expense (income) Income tax Profit (loss) Net loss for the period Net loss for the period Basic earnings (loss) per share Basic loss per share Diluted earnings (loss) per share Diluted loss per share Weighted average number of ordinary shares used in calculating basic earnings per share Weighted average number of shares outstanding used to calculate basic loss per share Weighted average number of ordinary shares used in calculating diluted earnings per share Weighted average number of shares outstanding used to calculate diluted loss per share The amount of dilution gain (loss) of associates accounted for using the equity method. Dilution Gain (Loss) Of Associates Accounted For Using Equity Method Dilution gain on investment in associate Statement of comprehensive income [abstract] Other comprehensive income that will be reclassified to profit or loss, net of tax Items that will be reclassified subsequently to profit or loss Items that will be reclassified subsequently to profit or loss Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, net of tax Currency translation differences - equity method Other comprehensive income, net of tax, exchange differences on translation of foreign operations Currency translation differences Exchange difference on translation of foreign operations Other comprehensive income that will not be reclassified to profit or loss, net of tax Items that will not be reclassified subsequently to profit or loss Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans Remeasurement of defined benefit plans Other comprehensive income Other comprehensive income Total other comprehensive loss Comprehensive income Total comprehensive loss Statement of changes in equity [abstract] Statement of changes in equity [table] Components of equity [axis] Components of equity [domain] Issued capital [member] Share capital Share premium [member] Premiums related to share capital Retained earnings, profit (loss) for reporting period [member] Net profit (loss) Reserve of exchange differences on translation [member] Translation Reserves This member represent a component of equity consisting of retained earnings excluding the current reporting period, and treasury shares. Retained earnings excluding profit (loss) from current reporting period and treasury shares [Member] Reserves (Accumulated losses) Statement of changes in equity [line items] Consolidated statement of changes in shareholders' equity Number of shares outstanding Balance at the end (in shares) Balance at the beginning (in shares) Number of shares outstanding Number of fully authorized, subscribed and paid up shares Other comprehensive income, net of tax, exchange differences on translation of foreign operations including effects of translation of investments accounted for using equity method Other comprehensive income, net of tax, exchange differences on translation of foreign operations including effects of translation of investments accounted for using equity method Currency translation differences Increase (decrease) through appropriation of retained earnings, equity Appropriation of net income (loss) Issue of equity Issue of ordinary shares Issue of equity The increase in shares resulting from the issuance of shares. Increase In Shares Through Issue of Ordinary Shares Issue of ordinary shares (in shares) Share issue related cost Transaction costs Transaction costs The increase (decrease) in equity resulting from the issuance of warrants. Increase Decrease Through Issuance Of Warrants, Equity Issue of prefunded warrants Increase (decrease) through exercise of warrants, equity Vesting of bonus shares Exercise of warrants Increase (decrease) through share-based payment transactions, equity Share-based payment compensation expenses Capital increase arising from the vesting of bonus share awards Increase (decrease) through treasury share transactions, equity Treasury shares Increase (decrease) through other changes, equity Other Classes of share capital [axis] Classes of share capital [domain] This member stands for T2 New Share. T2 New Share [Member] T2 New Share Information by type of sale of the entity's stock. IFRS Sale of Stock [Axis] Sale of the entity's stock, including, but not limited to, initial public offering (IPO) and private placement. IFRS Sale of Stock [Domain] This member stands for equity offering. Equity Offering [Member] Equity offering This member stands for registered underwritten public offering. Registered Underwritten Public Offering [Member] Registered underwritten public offering This member represents the 2024 Financing arrangement in three tranches, Tranche II. Financing arrangement in three tranches 2024, Tranche II [Member] Tranche II, 2024 Financing arrangement in three tranches Information by type of warrant or right issued. Ifrs Class of Warrant or Right [Axis] Name of the class or type of warrant or right outstanding. Warrants and rights represent derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Ifrs Class of Warrant or Right [Domain] This member stands for T2 BSA pre-funded warrants. T2 BSA Prefunded Warrants [Member] T2 BSA Prefunded Warrants The number of shares issued during the period. Stock Issued During Period, Shares Number of shares issued during the period Number of warrants issued Number of warrants issued Number of warrants issued Statement of cash flows [abstract] Cash flows from (used in) operating activities [abstract] Cash flows used in operating activities Adjustments to reconcile profit (loss) [abstract] Elimination of non-cash or non-operating income and expenses Adjustments for depreciation, amortisation expense and provisions to reconcile profit (loss) to net cash flow from (used in) operating activities. Adjustments for Depreciation, Amortisation and Provisions Depreciation, amortization and provisions Adjustments for gain (loss) on disposals of tangible and intangible assets to reconcile profit (loss) to net cash flow from (used in) operating activities. Adjustments For Gains (Losses)On Disposal Of Tangible and Intangible Assets Net book value of tangible and intangible assets disposed Adjustments for income tax expense Deferred and current taxes Adjustments for tax credit to reconcile profit (loss) to net cash flow from (used in) operating activities. Adjustments For Tax Credits Tax credits Adjustments for cost of debt. Adjustments for cost of debt Cost of debt Adjustments for share-based payments Share-based compensation expense Adjustments for undistributed profits of associates Share of net loss (profit) of associates and joint ventures accounted for using the equity method Adjustments for unrealised foreign exchange losses (gains) Exchange (gains) / losses Adjustments for fair value losses (gains) Fair value variation through profit and loss Other adjustments for non-cash items Other Cash flows from (used in) operations before changes in working capital Cash flows used in operations before tax and changes in working capital Adjustments for decrease (increase) in trade and other receivables Decrease / (increase) in operating and other receivables Adjustments for increase (decrease) in trade and other payables Increase / (decrease) in operating and other payables Income taxes paid (refund), classified as operating activities Tax credit received Other inflows (outflows) of cash, classified as operating activities Other Increase (decrease) in working capital Tax and changes in operating working capital Cash flows from (used in) operating activities Net cash used in operating activities Cash flows from (used in) investing activities [abstract] Cash flows provided by (used in) investing activities Purchase Of Property Plant And Equipment And Intangible Assets Classified As Investing Activities Purchase Of Property Plant And Equipment And Intangible Assets Classified As Investing Activities Purchases of property, plant and equipment and intangible assets Cash flows from (used in) decrease (increase) in short-term deposits and investments Decrease / (Increase) in short-term deposit accounts Cash flows from (used in) investing activities Net cash flows provided by (used in) investing activities Cash flows from (used in) financing activities [abstract] Cash flows provided by (used in) financing activities Proceeds from issuing shares Capital increase Proceeds from issuance of shares Payments for share issue costs Transaction costs related to capital increase Transaction costs related to capital increase The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt). IFRS Proceeds from Issuance of Warrants Issue of warrants The aggregate amount paid by the entity to reacquire the right to purchase equity shares at a predetermined price, usually issued together with corporate debt. IFRS Payments for Repurchase of Warrants Repurchase of prefunded Warrants Proceeds from borrowings, classified as financing activities Subscription of borrowings Loan obtained Repayments of borrowings, classified as financing activities Repayment of debt Repayments of borrowings Payments of lease liabilities, classified as financing activities Repayment of lease liabilities Repayment of lease liabilities Interest paid, classified as financing activities Interest paid Cash flows from (used in) financing activities Net cash flows provided by (used in) financing activities Increase (decrease) in cash and cash equivalents before effect of exchange rate changes Net increase (decrease) in cash and cash equivalents Effect of exchange rate changes on cash and cash equivalents Exchange gains / (losses) Adjustments for gain (loss) on lease modifications to reconcile profit (loss) to net cash flow from (used in) operating activities. Adjustments for Gain (Loss) on Lease Modification Gain on lease modification Adjustments for dilution gain (loss) of investments accounted for using the equity method to reconcile profit (loss) to net cash flow from (used in) operating activities. Adjustments for Dilution Gain (Loss) from Investment in Associate using Equity Method Dilution gain on investment in associate Adjustments for decrease (increase) in prepaid expenses Variation of prepaid expenses The amount of cash outflow associated with the advance payment related to borrowings. Payment of Advance Related to Borrowings Advance payment related to Lenders' Tranche B under Debt Financing agreement No definition available. Company information. The entire disclosure on company information. Company Information [Text Block] Company information N/A Basis of preparation and statement of compliance The entire disclosure for basis of preparation and statement of compliance. Basis of preparation and statement of compliance [text block] Basis of preparation and statement of compliance No definition available. Accounting principles Disclosure of material accounting policy information [text block] Accounting principles No definition available. Notes to the unaudited interim condensed consolidated statement of financial position The entire disclosure for notes to the interim consolidated balance sheet. Disclosure of Notes to the Interim Condensed Consolidated Statement of Financial Position [Text Block] Notes to the unaudited interim condensed consolidated statement of financial position No definition available. Notes to the interim condensed consolidated statement of income (loss) The entire disclosure for components of income statement. Disclosure Of Components Of Income Statement [Text Block] Notes to the interim condensed consolidated statement of income (loss) No definition available. Other financial information The entire disclosure for other financial information. Disclosure Of Other Financial Information [Text Block] Other financial information Disclosure of accounting judgements and estimates [text block] Use of estimates and judgment Description of accounting policy for fair value measurement [text block] Fair value measurement Specific disclosure requirements for unaudited interim financial statements. Description Of Accounting Policy For Specific Disclosure Requirements For Unaudited Interim Financial Statements [Policy Text Block] Specific disclosure requirements for unaudited interim financial statements Disclosure of going concern [text block] Going concern Disclosure of interests in subsidiaries [text block] Schedule of subsidiaries Disclosure of effect of changes in foreign exchange rates [text block] Schedule of exchange rates Disclosure of fair value of financial instruments [text block] Schedule of financial assets and liabilities measured at fair value Disclosure of terms and conditions of share-based payment arrangement [table] Types of share-based payment arrangements [axis] Types of share-based payment arrangements [domain] This member stands for BSPCE and BSA share warrants. BSPCE and BSA Share Warrants BSPCE share warrants and BSA share warrants This member stands for bonus share award plans. Bonus Share Award Plans [Member] Bonus share award plans (AGA) AGA Share options [member] Stock options Disclosure of terms and conditions of share-based payment arrangement [line items] Notes to the unaudited interim condensed consolidated statement of financial position Disclosure of detailed information about intangible assets [text block] Schedule of intangible assets Disclosure of reconciliation of changes in property, plant and equipment, including right-of-use assets [text block] Reconciliation of changes in property, plant and equipment Disclosure of reconciliation of summarised financial information of associate accounted for using equity method to carrying amount of interest in associate [text block] Schedule of investment in Hepalys is accounted for using the equity method of accounting The tabular disclosure of other non current assets. Disclosure Of Other Noncurrent Assets [Table Text Block] Schedule of other non current assets The tabular disclosure of trade receivables. Disclosure of Trade Receivables [Table Text Block] Schedule of trade receivables and others break down Disclosure of other current assets [text block] Schedule of other current assets and receivables The tabular disclosure of cash and cash equivalents. Disclosure Of Cash And Cash Equivalents [Table Text Block] Schedule of cash and cash equivalents balance from the statement of cash flows Disclosure of classes of share capital [text block] Schedule of changes in share capital Disclosure of number and weighted average exercise prices of other equity instruments [text block] Schedule of movements in BSPCE and BSA share warrants and AGA Disclosure of indirect measurement of fair value of goods or services received, share options granted during period [text block] Schedule of measurements for share options granted Disclosure of terms and conditions of share-based payment arrangement [text block] Schedule of main characteristics of share-based payment plan Disclosure of number and weighted average exercise prices of share options [text block] Schedule of stock option plans Tabular disclosure of input and valuation technique used to measure fair value of European Investment Bank Warrants. Schedule Of Valuation Approach For European Investment Bank Warrants [Table Text Block] Schedule of valuation approach for European investment bank warrants Disclosure of detailed information about borrowings [text block] Schedule of Debt, Derivatives and Royalty Certificates liabilities Disclosure of reconciliation of liabilities arising from financing activities [text block] Schedule of changes in liabilities Disclosure of valuation approach for European Investment Bank warrants. Disclosure of valuation approach for European Investment Bank warrants [table text block] Schedule of valuation approach for EIB warrants Disclosure of valuation approach for lenders' warrants. Disclosure of valuation approach for lenders' warrants [table text block] Schedule of valuation approach for lenders' warrants Disclosure of other provisions [text block] Schedule of provisions The disclosure of detailed information about provision recorded in respect of defined benefit schemes at the end of each reporting period. Disclosure Of Provision Recorded In Respect Of Defined Benefit Schemes At End Of Each Reporting Period, Explanatory Schedule of provision recorded in respect of defined benefit schemes at the end of each reporting period The disclosure of detailed information about change in the provision recorded in respect of defined benefit schemes. Disclosure Of Changes In Provision Recorded In Respect Of Defined Benefit Schemes, Explanatory Schedule of change in the provision recorded in respect of defined benefit schemes