My fiancee and I are looking at a trip to Paris, by way of Paris, to Istanbul.

IAD - CDG - IST // IST - CDG // CDG - IST // IST - AMS - IAD

First off -- if we choose to fly through IST and then head to back to Paris (whether on Skyteam or a different airline), is it possible we could get in trouble?

Second -- what's the minimum transfer time in CDG? Obviously, we'd have to pass customs in Paris, and then get to a plane to Istanbul (where we'd hang out for a few days) -- the time the flight we are looking at is only 70 minutes. That seems dangerous to me. Thanks!!!