Themroc (1972)
A film by Claude Faraldo


Themroc (Michel Piccoli) goes to work one morning, the same as every morning, but there's a difference this time - as the day draws on, Themroc realises he's had enough of the same old routine. While up a ladder to paint the outside of an office block, he ogles the secretary being dictated to by his boss, then his boss catches him and calls him into his office. This causes Themroc to snap, and he walks out with plans to send himself back to the stone age...

 http://www.thespinningimage.co.uk/cultfilms/displaycultfilm.asp?reviewid=509

Themroc is fired by his boss. He goes into a toilet cubicle and grunts and growls loudly, like a mad dog. On his way home he enters a subway station. He walks down the line into the tunnel, howling at the passing trains. Themroc arrives home and is greeted at the door by his sister, who has her breast showing. He fondles her and she seems to like it. He then gets a sledgehammer and knocks a huge hole in the wall of his flat. He throws out his television and other appliances onto the forecourt below. He enters and leaves his flat via a rope ladder dangling from the hole. Soon, other neighbours start to knock holes in their walls, too.
The police eventually arrive, some in riot gear. Themroc and his sister throw anything they can find in the house at them in the forecourt below. The police throw tear gas cannisters in Themroc's flat, but he soon gets rid of them and gleefully throws them back and forth with his neighbours, who are all now behaving like Themroc.
 http://www.wayney.pwp.blueyonder.co.uk/themroc.htm