PARIS (Reuters) - The man opinion pollsters tip to become France's next president said on Friday it would be an error to compare him to Hillary Clinton, who was widely expected to become U.S. president but lost to Donald Trump.

"I am not Hillary Clinton," poll frontrunner Alain Juppe said. "And France is not America."

The 71-year-old former prime minister was speaking on public radio ahead of a primary election ballot his conservative Les Republicains party and its allies hold on Sunday. That contest, involving a second, run-off vote on Nov. 27, will pick a candidate for the presidential race.

He is up against other heavyweights including ex-president Nicolas Sarkozy and another former prime minister, Francois Fillon, respectively second- and third-placed in polls of the likely outcome of that primary.

After a U.S. election that defied opinion poll predictions and general media expectations, the French media are asking whether a similar upset could occur this side of the Atlantic, in the primary, or in the presidential election itself, which takes place in two rounds next April and May.

Juppe is the pollsters tip to win in both cases, though the latest surveys suggest his lead has slipped significantly and made the result much harder to call.

Both rivals have closed the gap, with Sarkozy in second place and Fillon's support growing fast. A flash poll made Fillon the winner of a TV debate between primary election candidates on Thursday night.

(Reporting By Brian Love; Editing by Andrew Callus)