Montpellier has a few rather shady characters especially once it gets dark, but a really lovely town. Very relaxed and pleasant.
I´ve been in Montpellier for about 2 months and I love it. It's not as touristy as other towns in southern France, but it's still beautiful! Wander around the Comdie, go shopping, have some crepes, and party at night with friendly people. What more could you want?
Sète Sete has beautiful beaches and it's a great medium-small town that isn't trampled by tourists.
Montpellier is like an international student town. That's why it's so young, and old for its monuments and buildings. You must pay attention to the dogshit... it's everywhere!! In cyber-cafes you must be careful of your belongings. And those shady characters are the kings of the city on Sundays!! The bars are close on 1 AM in the city center, but there are the special buses to after parties out of town. These are the great clubs with entrance fees (generally 10€ including 1 free drink) and there are after after parties on the beach. Enjoy!
I found that Montpellier was quite disgusting, a terrible place to holiday.
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