Rise of Trump is 'scary' - ex-France president

Donald Trump is "scary" and his popularity in the United States is worrying, former French President Nicolas Sarkozy said Wednesday.

"This man does not deserve as much attention as he gets. What is so scary is the impact he has," the leader of France's Republicans party said at an event in London.

"It makes me shudder. It makes me shudder about the state of a part of the American heartland," said Sarkozy, who led France between 2007 and 2012.

He criticised the "populism" and "vulgarity" of Trump's campaign, which has been marked by controversial statements about Muslims, as the real estate mogul closes in on his Republican Party's nomination for presidential candidate.

Sarkozy's time as president marked a warming of ties between Paris and Washington, after several years of chill under his predecessor.

After a short period out of the limelight, the 61-year-old has his eyes on another run for the presidency in 2017, but faces corruption charges relating to influence peddling.