The vandalism ups the ante in the series of long-running protests against planned tuition hikes.
Three people were arrested for participating in an illegal gathering, while another three were detained for mischief and participating in an illegal gathering, police said.
The seventh person was arrested for break-and enter.
The arrests took place shortly after about 15 people smashed two windows and then vandalized Education Minister Line Beauchamp's office in her riding of Bourassa-Sauve.
The vandalism came a day after provincial police announced the arrest of a man for allegedly threatening a Quebec cabinet minister.
They also said two other investigations are underway involving alleged threats against two ministers.
Police refused to name the ministers in question, but some media identified them as Beauchamp and Justice Minister Jean-Marc Fournier.
Also on HuffPost