hi steve,
going to paris and looking for modeller's shops? mmmmmmmmmmh... sounds unsafe! I mean, if you are travelling in pair...
nowadays it's so easy to shop by web, and paris it's so big and full of other attractions, that going for shops seems (to me) a waste of time!
planning a couple of days out of paris, I suggest you to going to caen just to the memorial, otherwise you'll be trapped in traffic jams just like in paris...
I was there last year, and found to sleep in BB on the coast, visiting a number of beautiful historic spots and landscapes.
a must it's the restaurant "l'estaminet", in saint marie du mont, behind utah beach. I'm not a gourmet, but as italian, I love the good food, and I'm suspicious about the french chefs. believe me, if I say go there.... go!
have a nice trip, p.