Two French presidential hopefuls have snubbed former prime minister Edouard Philippe's call to join forces as centrists struggle to unite against the far right in next year's presidential election.

Lawmakers are expected to question the French leader about his plans post-2027 in the wake of the far right victory in Germany, a party official says.

Supporters of centrist former PMs Edouard Philippe and Gabriel Attal fear they are fighting each other more than the far right and far left.