Press Release

Cellectis S.A. announces the launch of its initial public offering on the Alternext market of Euronext Paris.

Guide price: between €8.90 and €10.25 per share

Romainville, France - January the 23^rd, 2007 - Cellectis S.A., a biotechnology company specialized in genome engineering and developing a new range of products for the custom rewriting of DNA sequences for the research, healthcare and industrial fields, today announced the launch of its initial public offering with a view to listing its shares on the Alternext market of Euronext Paris.

The stock market listing should enable Cellectis S.A. to raise at least 16 million euros, including 2.7 million as part of a reserved offering for the company's employees, officers & shareholders and certain individuals having contributed to the company's development. The net product of the issue will be around 14.6 million euros, rising to around 19.4 million euros in the event of full exercise of the extension facility and the over-allotment option (the "greenshoe").

The offering will run from January 23, 2007 until February 5, 2007 at 5pm for the Open Price Offering and from January 23, 2007 until February 6, 2007 at midday for the Global Offering. The final offer price will be fixed on February 6, 2007.
The offering and the listing of Cellectis shares for trading on the Alternext market of Euronext Paris are aimed at providing Cellectis S.A. with additional resources for financing its operations, which notably include:

• increasing its current production capacity in order to achieve a figure of 20 MRSs (Meganuclease Recombination Systems) per year by 2008,
• reinforcing its sales, marketing and PR teams, and
• intensifying the company's R&D efforts on both meganuclease engineering and the MRS production process.

"The funds raised, as part of our stock market listing, will support our strategy, which consists in establishing Cellectis' technology as the standard in genome engineering", emphasized André Choulika, co-founder and Chief Executive Officer of Cellectis. "Cellectis has already completed a number of major investments in developing its technology platform, and the funds raised will enable us to finance the design of new MRSs and to move from an annual MRS production capacity of 8 in 2006 to 20 in 2008, to take on new staff dedicated to MRS production and commercialization, to reinforce our existing collaborations and initiate new ones", André Choulika added.

Cellectis has developed the first ever technology for industrial-scale in vivo genome engineering and the company's technology platform enables it to design MRSs (like "copy-pasting" DNA) - a true technological breakthrough in the biotechnology world. In fact, all of the industrial biotech applications, introduced over the last few decades, have involved random gene insertion, whereas the Cellectis MRSs enable the precise insertion, modification, modulation and correction of a gene in any living organism (humans, plants or micro-organisms) or cell.
Since its foundation (and up until 2006), Cellectis has sold sublicenses to technology from the Pasteur Institute and has signed 45 commercial agreements with leading pharmaceutical, agrichemicals and biotech companies. Over the same period, Cellectis developed its own technology for designing and producing custom meganucleases and has thus been selling MRSs since 2006.
Today, Cellectis has an MRS production capacity of 8 per year and aims at scaling up to 20 per year by 2008. Commercialization of the MRSs started in 2006 and has already resulted in an initial agreement with a multinational agro-industrial company.
The MRSs produced by Cellectis are (and will continue to be) sold to industrial customers who then apply them in Cellectis' three target markets: biotherapeutics, agriculture and biomanufacturing. In parallel, Cellectis intends to pro-actively spread its technology as a research tool (notably for major academic labs), so that the MRS becomes a benchmark technology.

About Cellectis S.A.

Cellectis S.A. is a biotech company developing innovative, proprietary technologies for genome engineering: a new class of "molecular scissors" - Meganuclease™ enzymes - capable of recognizing, binding and cutting DNA with extremely high specificity. The company is developing and commercializing Meganuclease Recombination Systems (MRSs) which combine these molecular scissors with a DNA matrix for targeting and modifying a gene of interest in vivo (and without affecting the rest of the genome) via the action of the cell's natural maintenance and repair system. By developing this first-in-class technology on the industrial scale, Cellectis has opened the way to rational genome engineering, which seeks to accurately and reliability insert, modify, modulate or correct genes in any living organism - without the addition of foreign genes, which are often imprecise and poorly tolerated. Cellectis now holds a portfolio of 8 MRSs in development, of which 5 have a therapeutic focus.
Founded in 2000 by André Choulika and David Sourdive, Cellectis is a spin-off from Institut Pasteur in Paris, which has granted the company exclusive rights on 26 of the 27 patents and on 38 of the 69 pending applications in Cellectis's today portfolio (one of which will fall into the public domain in 2009, with six others in 2010). Since its creation, Cellectis has raised 17.5 million euros in two rounds (in 2000 and 2002/2005) to support its R&D and commercial development. The company's principal shareholders are AGF Private Equity, BankInvest Biomedical Venture, Edmond de Rothschild Investment Partners, Kaminvest Holding and Odyssée Venture. To date, Cellectis has signed 45 collaboration agreements and alliances worldwide with pharma companies (including AstraZeneca, Merck & Co., Wyeth and Shire), agrochemical groups (including Bayer, DuPont and BASF) and biotech companies (including Genentech, Regeneron and Lexicon Genetics) worldwide.
Cellectis' corporate headquarters are located on the Biocitech biopark at Romainville near Paris. It currently has 40 staff, including 16 PhDs.
For more information on Cellectis, visit our web site: www.cellectis.com

Availability of the prospectus

Copies of the prospectus approved by the French Autorité des marchés financiers ("AMF") on January 22, 2007 under visa number 07-023 are available free of charge from Cellectis S.A, 102, route de Noisy, 93230 Romainville, France, and on the websites of the AMF (http://www.amf-france.org) and Cellectis (http://www.cellectis.com). The French prospectus includes the document de base registered with the AMF on December 22 2006 under number I.06-198, the note d'opération and a summary.

Risk factors

Cellectis draws the attention of the public to the risks set out in Chapter 4 of the document de base and in Chapter 2 of the note d'opération.

This press release, and the information contained herein, do not constitute an offer to sell or a solicitation of an offer to buy or subscribe for shares in Cellectis in any country.

Shares in Cellectis may not be sold in the United States of America absent registration or an exemption from registration under the U.S. Securities Act of 1933, as amended. There will be no registration of all or part of the offering referred to in this press release in the United States of America nor any public offering of Cellectis in the United States of America. This press release may not be distributed, in particular, either directly or indirectly, in the United States of America and does not constitute an offer to sell securities in the United States of America.