Harlequins can’t finish top of Pool Four and need a lot of luck and two bonus-point wins against Castres (second in the pool with 11 points) and Munster (1st, 14) to proceed to the quarter-finals.
The French will fancy their chances of reaching the next round having won their last six home Heineken Cup ties, including decisive victories over Munster and the Ospreys this season.
They may be three points adrift of table-topping Munster, but a third home win would give them everything to play for in their final game in Wales.
Quins have opted to start Andy Dunne at fly-half and he replaces Jeremy Staunton, who drops to the bench.
In the front row, Ace Tiatia starts at hooker in place of James Hayter, who misses out due to a groin injury.
Karl Rudzki and Simon Miall are in the second row in place of Roy Winters and Simon Maling.
: Metcalfe; Raffault, Marticorena, Denney, Mola; Delaigue, Albouy; Reggiardo, Vigneaux, Galasso, Nallet, Spanghero, Bernad, R Capo Ortega, Volley.
: Argenese, F Capo Ortega, Deen, Froment, Dourthe, X Sadourny, Morlaes.
: Duffy, Harder, James, Deane, Keogh, Dunne, So’oialo, Jones, Tiatia, Dawson, Rudzki, Miall, Molitika, Sherriff (capt), Hortsmann.
: Dott, Muggeridge, Easter, Diprose, Staunton, Reay, Williams.
: Donal Courtney (Ireland).