If you're truly interested in both subjects then i'm sure you'll manage fine, though both together can be quite demanding as french is rather time-consuming what with language classes as well as the literature stuff - i ended up dropping it after one semester because i didn't enjoy it enough to dedicate that much time to it. And psych can get quite difficult as well, especially for an arts student when they get into all the biological stuff.
As to Dundee/Edinburgh, me and my friends end up in dundee quite often, it's loads of drunken fun
You're less likely to go out in edinburgh if you don't know someone who lives there though.
[hr]
The shadow proves the sunshine...
"This is my story. It'll go the way I want, or I'll end it here"
--Final Fantasy X