Visa question

I am planning to leave on a 8 months journey from September 27 to May 31st. I am planning to buy a Montreal-Paris roundtrip plane ticket. I haven't gotten a visa as I am a Canadian citizen and I will be spending less than 90 days in Europe, and then move to Asia for a few months and come back through Russia in April. Therefore, I will never be in Schengen territory more than 90 days for any given 6 months period.
Could I get trouble getting in France since my return ticket is 8 months later and could give the impression I won't be respecting my "automatic" 3-months visa?? I don't have any "proof" that I will go to Asia, I really don't want to book whatever mean of transportation I'll be using to get there as my itinerary is not precise yet.