PARIS, Dec 1 (Reuters) - French riot police used teargas on Saturday against protesters clad in fluorescent yellow trying to break through security cordons at the Champs Elysees in Paris.

A Paris police spokeswoman said 16 people had already been arrested. Officials fear far-right and far-left groups plan to infiltrate the yellow vests movement, a popular rebellion against diesel tax hikes and the high cost of living. (Reporting by Emmanuel Jarry; editing by John Irish)