Police in Paris have detained a man believed to be the one shown in a viral video attacking a studentoutside a city cafe last month. Authorities reportedly arrested the man on Monday after he left a psychiatric hospital on suspicion of assault and sexual harassment.

The shocking incident was captured on the cafe's CCTV footage and then shared online by the victim, 22-year-old Marie Laguerre (above).

Laguerre wrote on Facebook that she was walking home past the restaurant when the man began using "dirty language, in a humiliating and provocative manner."

"I told him to shut up and kept walking away, because I can't stand this kind of behaviour. I can't keep quiet, and we mustn't keep quiet any longer," she wrote.

In the video, the man can be seen punching Laguerre (left)

Then, as can be seen in the footage, the man threw an ashtray at her and hit her in the face, in front of shocked witnesses.

Laguerre was due to identify the suspect on Tuesday.

Just a few days after the assault, the French parliament passed a law forbidding catcalling in the street as part of a larger bill targeting sexist crimes. The law also covers following women on the street and taking sexual pictures of a woman without her knowledge.