I am sorry for your experience. We own a condo on the French side and have been stopped at a checkpoint a few times. The Gendarmes were always polite and respectful. We have never, ever been asked for our passports, as we do not carry them. We do carry our rental contract and our driver's licenses, but rarely been asked for them. Usually, after we speak a few words in English, the wave us through. I believe they're main focus is finding illegals. We spend most (90%) of our time on the French side.