v3.26.1
Cover Page - shares
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2023
Document Information [Line Items]    
Document Type 20-F  
Amendment Flag false  
Document Period End Date Dec. 31, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus FY  
Entity Registrant Name CELLECTIS S.A.  
Entity Central Index Key 0001627281  
Current Fiscal Year End Date --12-31  
Entity Well-known Seasoned Issuer No  
Entity Current Reporting Status Yes  
Entity Filer Category Accelerated Filer  
Entity Shell Company false  
Entity Emerging Growth Company false  
Title of 12(b) Security Ordinary shares, nominal value €0.05 per share*  
Security Exchange Name NASDAQ  
Document Registration Statement false  
Document Annual Report true  
Document Transition Report false  
Document Shell Company Report false  
Entity Voluntary Filers No  
Entity Interactive Data Current Yes  
Entity Address, Country FR  
ICFR Auditor Attestation Flag true  
Document Financial Statement Error Correction [Flag] false  
Entity Address, Address Line One 8, rue de la Croix Jarry  
Entity File Number 001-36891  
Entity Incorporation, State or Country Code I0  
Entity Address, City or Town Paris  
Entity Address, Postal Zip Code 75013  
Document Accounting Standard International Financial Reporting Standards  
No Trading Symbol Flag true  
Auditor Firm ID 1253 1704
Auditor Name KPMG S.A. Ernst & Young et Autres
Auditor Location Paris-La Defense, France Courbevoie, France
Auditor Opinion

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated statements of financial position of Cellectis S.A. and subsidiaries (the Company) as of December 31, 2025 and 2024, the related statements of consolidated operations, consolidated comprehensive income (loss), consolidated cash flows and changes in consolidated shareholders’ equity for the years then ended, and the related notes (collectively, the consolidated financial statements). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for the years then ended, in conformity with IFRS Accounting Standards as issued by the International Accounting Standards Board.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission, and our report dated March 19, 2026 expressed an unqualified opinion on the effectiveness of the Company’s internal control over financial reporting.

  
Ordinary shares [member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding 72,339,441  
Class A convertible preferred shares [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding 10,000,000  
Class B convertible preferred shares [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding 18,000,000  
American Depository Shares [Member]    
Document Information [Line Items]    
Title of 12(b) Security American Depositary Shares, each representing one  
Security Exchange Name NASDAQ  
Trading Symbol CLLS  
Business Contact [Member]    
Document Information [Line Items]    
Entity Address, Country FR  
Entity Address, Address Line One 8, rue de la Croix Jarry  
Entity Address, City or Town Paris  
Entity Address, Postal Zip Code 75013  
Contact Personnel Name Marie-Bleuenn Terrier  
Country Region 33  
City Area Code 1  
Local Phone Number 1 81 69 16 00  
Contact Personnel Fax Number +33 (0)1 81 69 16 06