The students are protesting the Government's plan to increase tuition by 325$ a year until 2017. Here's a graph of the historical tuition costs in Quebec. Included are the inflation adjusted tuition costs in 2012 dollars. You can see that if the government plan goes through Quebec well see the highest tuition costs in over 40 years. That's probably what's got the students upset.
Click to zoom in
Inflation adjusted values calculated using the Bank of Canada's inflation calculator:
Projected inflation is 2% per year from 2013 - 2017.
Historical tuition fees taken from here: