You were given a visa for a long stay which is valid for 3 months, time normally sufficient to apply for and get a "carte de séjour".
To travel within the Schengen area: every Schengen country has signed a bilateral agreement with Canada allowing their respective nationals to travel for a maximum of 3 months in the other country. Threfore, though you have spent already more than 3 months in France, you are allowed to travel through the Schengen area. As there is no immigration control between Schengen countries, your passport should not be stamped.
If you leave the Schengen area, normally you can reenter France with the "recepisse" you got from the préfecture. Did you get it? If not, you should go to the préfecture and enquire. Anyway, the bilateral visa waiver agreement between France and Canada allows Canadians to remain in France for 3 months irrespective of any former stay in France. Therefore, when you enter France, you are entitled to a 3 months stay, even without a visa.