I've contacted Geoboutique, the organism in charge of diffusing geographical data for the Government of Québec and they asked me to indicated the source of the trails as Adresses Québec (© Gouvernement du Québec), but that the use of the data was in accordance with the license.

I'll correct this.

The tracks are from AQréseau+, under Creative Common 4.0.
I'll indicate it more clearly from now on.

I'm rather new to OSM and I rather leave the tags in as they contain information about road quality and number of lanes.