Yesterday me and my friend coming from Germany to visit Paris. Then we used 6 line Metro. We took our tickets. It was valid and no problem. Then we showed on the corner two controller. They asked for the tickets and i showed our tickets. Then i asked to my friend. I said we came together. Then they said no we can't know that there is no proof you were together. And took from us 50€. Even if we have our tickets. That was so rude to us as a tourist. What i am suppose to do?
Thanks