Complex sentence: The reactionary French "Patriots" interrupted the screening by throwing ink at the cinema screen and assaulting viewers who opposed them; they then went to the lobby and destroyed art works by Dalí, Joan Miró, Man Ray, Yves Tanguy, and others.
Split into simpler sentences: The reactionary French "Patriots" interrupted the screening by throwing ink at the cinema screen and assaulting viewers who opposed them. They then went to the lobby and destroyed art works by Dalí, Joan Miró, Man Ray, Yves Tanguy, and others.