Mermoz's place at inside centre has been taken by the versatile Damien Traille who switches from the full-back position to form a sturdy midfield combination with Aurelien Rougerie.
The one and only change in personnel from the Scotland match sees Clement Poitrenaud return at full-back for les Bleus.
Of the team that beat Ireland 33-10 in Paris twelve months ago, only Poitrenaud and half-backs Francois Trinh-Duc and Morgan Parra remain in the backs.
Marc Lievremont fields the same front row of Thomas Domingo, William Servat and Nicolas Mas, while lock Lionel Nallet, team captain Thierry Dusautoir and number 8 Imanol Harinordoquy are also survivors from the sides' 2010 meeting.
Yannick Jauzion, who started that game at centre alongside Mathieu Bastareaud, has been added to the French replacements bench along with prop Sylvain Marconnet.
Experienced centre Jauzion missed today's training session with a shoulder complaint, but is not doubtful for the weekend.
Lievremont said: "We go with stability. I think Damien is better physically and mentally than he was in November. I liked his performance at the back. He can play in many positions."
FRANCE Team & Replacements (v Ireland, 2011 RBS 6 Nations Championship, Aviva Stadium, Sunday, February 13, kick-off 3pm):
15. Clement Poitrenaud (Toulouse)
14. Yoann Huget (Bayonne)
13. Aurelien Rougerie (Clermont Auvergne)
16. Guilhem Guirado (Perpignan)
17. Sylvain Marconnet (Biarritz Olympique)
18. Jerome Thion (Biarritz Olympique)
19. Sebastien Chabal (Racing Metro 92)
20. Dimitri Yachvili (Biarritz Olympique)
21. Yannick Jauzion (Toulouse)
22. Vincent Clerc (Toulouse)