French police are reportedly investigating allegations former All Blacks rugby player Jerry Collins assaulted a woman.

Collins, who played 48 tests before retiring from New Zealand rugby last March, is playing for French club Toulon and denies the allegation.

Two French newspapers were reporting differing accounts of the alleged incident, New Zealand's TV3 said on Wednesday night.

One said a woman claimed Collins pushed her into a gully, while another said she fell five metres into a gully as she tried to get into Collins' house after following him home.

"I am morally and physically shattered. I had to spend six weeks on my back. I have a fractured sacrum, bruises, a twisted spine and a fractured wrist," one newspaper reported the woman as saying.

Toulon Rugby Club was standing by Collins.

"We have made our own inquiries and it appears to us, according to witnesses we gathered together, that the player did nothing," the club said.

Police are expected to make a decision on charges in the next few days.

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