The 21-year old farm worker was caught on Sunday after a series of incidents that shocked women who were out jogging in a wood 30 kilometres north west of Grenoble.
Several women reported being startled by a man wearing a hooded top and who was apparently armed. Police spokesman Michel Aragon told Le Progrès newspaper "he pretended he was working for the police and was there to help. He warned them about the risks they were taking by running alone in the wood."
On 9th June, the man went further when he asked one of the joggers to take down her trousers, causing her to burst into tears.
"He went from being menacing to trying to calm her down," said Aragon.
He lowered his hood which then allowed police to get enough information to issue a clear description.
France has had a string of attacks on female joggers in recent months. The most recent was two weeks ago when a 17-year old student, Marie Jeanne Meyer, was murdered while out jogging in Tournon-sur-Rhône in the Ardèche.
The man was released on Monday and will undergo further psychiatric tests.