Financial liabilities - Royalty certificates (Details) - EUR (€) € / shares in Units, € in Thousands	Jun. 30, 2025	Dec. 31, 2024
Disclosure of detailed information about borrowings [line items]
Financial liabilities, at fair value	€ 160,067	€ 162,256
Share price
Disclosure of detailed information about borrowings [line items]
Amount of reasonably possible increase in unobservable input, liabilities	€ 1	€ 1
Royalty certificates
Disclosure of detailed information about borrowings [line items]
Financial liabilities, at fair value	€ 9,417	€ 7,313
Royalty certificates \| POS
Disclosure of detailed information about borrowings [line items]
Percentage of reasonably possible increase in unobservable input, liabilities	5.00%	5.00%
Increase (decrease) in financial liabilities at fair value due to reasonably possible increase in unobservable input	€ 740	€ 572
Percentage of reasonably possible decrease in unobservable input, liabilities	(5.00%)	(5.00%)
Increase (decrease) in financial liabilities at fair value due to reasonably possible decrease in unobservable input	€ (740)	€ (572)
Royalty certificates \| Peak penetration
Disclosure of detailed information about borrowings [line items]
Percentage of reasonably possible increase in unobservable input, liabilities	5.00%	5.00%
Increase (decrease) in financial liabilities at fair value due to reasonably possible increase in unobservable input	€ 2,201	€ 1,735
Percentage of reasonably possible decrease in unobservable input, liabilities	(5.00%)	(5.00%)
Increase (decrease) in financial liabilities at fair value due to reasonably possible decrease in unobservable input	€ (3,182)	€ (2,527)
Royalty certificates \| WACC
Disclosure of detailed information about borrowings [line items]
Percentage of reasonably possible increase in unobservable input, liabilities	1.00%	1.00%
Increase (decrease) in financial liabilities at fair value due to reasonably possible increase in unobservable input	€ (395)	€ (314)
Percentage of reasonably possible decrease in unobservable input, liabilities	(1.00%)	(1.00%)
Increase (decrease) in financial liabilities at fair value due to reasonably possible decrease in unobservable input	€ 416	€ 332
Royalty certificates \| Share price
Disclosure of detailed information about borrowings [line items]
Amount of reasonably possible increase in unobservable input, liabilities	€ 1	€ 1
Increase (decrease) in financial liabilities at fair value due to reasonably possible increase in unobservable input	€ 1,326	€ 1,160
Amount of reasonably possible decrease in unobservable input, liabilities	€ (1)	€ (1)
Increase (decrease) in financial liabilities at fair value due to reasonably possible decrease in unobservable input	€ (1,326)	€ (1,160)

Amount Of Reasonably Possible Decrease In Unobservable Input, Liabilities

No definition available.

Name:	abvx_AmountOfReasonablyPossibleDecreaseInUnobservableInputLiabilities
Namespace Prefix:	abvx_
Data Type:	dtr-types1:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount Of Reasonably Possible Increase In Unobservable Input, Liabilities

+ References

No definition available.

+ Details

Name:	abvx_AmountOfReasonablyPossibleIncreaseInUnobservableInputLiabilities
Namespace Prefix:	abvx_
Data Type:	dtr-types1:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2025-01-01
-Paragraph 25
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_25&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_FinancialLiabilitiesAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of increase (decrease) in the fair value measurement of liabilities due to a reasonably possible decrease in an unobservable input.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2025-01-01
-Paragraph 93
-Subparagraph h
-Clause ii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_h_ii&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleDecreaseInUnobservableInputLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of increase (decrease) in the fair value measurement of liabilities due to a reasonably possible increase in an unobservable input.

+ References

+ Details

Name:	ifrs-full_IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of a reasonably possible decrease in an unobservable input used in fair value measurement of liabilities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 13
-IssueDate 2025-01-01
-Paragraph 93
-Subparagraph h
-Clause ii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_h_ii&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_PercentageOfReasonablyPossibleDecreaseInUnobservableInputLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	dtr-2022:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of a reasonably possible increase in an unobservable input used in fair value measurement of liabilities.

+ References

+ Details

Name:	ifrs-full_PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	dtr-2022:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ifrs-full_UnobservableInputsAxis=abvx_SharePriceMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=abvx_RoyaltyCertificatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_UnobservableInputsAxis=abvx_ProbabilityOfSuccessMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_UnobservableInputsAxis=abvx_PeakPenetrationMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_UnobservableInputsAxis=ifrs-full_WeightedAverageCostOfCapitalMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: