Nearly 700 people have been detained in two Quebec cities in the biggest single night of mass arrests since student protests over fees began in February.
Police invoked a controversial new law designed to curb demonstrations as they detained 518 people in Montreal and another 176 in Quebec City.
The protests against a planned rise in tuition charges escalated after Bill 78 passed last week.
The Quebec government insists it will not change its mind on the fee hike.
The march in Montreal late on Wednesday began peacefully, as several thousand demonstrators flooded the central square of Quebec’s largest city.