We will be visiting Paris in September and we would like to go to the Opera for one evening. As we are travelling in Europe for 4 weeks by train, needless to say we wont have an overly dressy set of clothes. There is one Ballet that looks like fun, but the only night we could possibly attend is the opening night. Will we stick out like a sore thumb if we are dressed casually on opening night? Is this a serious faux pas? Also, how hard is it to get tickets for something like this? I see on the website they go on sale July 2. Do I have to be ready at 12:01 Paris time to get tickets? Or are they usually not too hard to get? Also, do you have to have an account online to get tickets?
Thanks for any help or suggestions!!