PARIS — The first Yellow Vest demonstration of the new year reached a new level of violence on Saturday as a government ministry building was attacked and the minister evacuated out the back door. What started two months ago as a protest over gas taxes has turned into a more general attack on the French government.

The minister, the chief government spokesman Benjamin Griveaux, told French television that Yellow Vest protesters and “men dressed in black” — the so-called casseurs, or “breakers,” who have latched onto the movement — commandeered a construction vehicle and broke down the door of the Left Bank building. They then entered a courtyard and broke several windows, he said.