Sorry Blossom,
I've been away for the weekend, so only just seen this (what, me, browse at work - with my reputation ).
I think LostinParis is probably quite right, there is only so much you can do from 'booklarning', but I did find one or two helpful simply to guide me about what questions to begin to ask.
Two best, in my experience, were Alan Hart's book, called (I think) Living and working in Paris and David Hampshire's book Living and Working in France. Both pretty good on the paperwork aspects, and for checklists of day to day stuff and the logistics of organising moves.
Ignore the chapters in Alan Hart's book about the nature of the arrondissement since 1) they'll be out of date and 2) they're obviously pretty subjective: you might find you love areas the author's run down.
But I think my motto here would be: 'time spent on the web is time rarely (really?) wasted'. Some sites I have found quite helpful: the french embassy in London (good for paperwork, wrestling with French taxation law etc), BBC site (for basic assessment of your language, some good french courses and quite a lot about becoming an expat) and the various Mairies (town halls) of the arrondissements (although their sites are largely in French) for things like childcare arrangements in each district and what the facilities are like. I think the Telegraph website also has an expat forum where you can find expat 'mentors': quite how helpful they will be is hard to say.
Anyway, when are you going over? Are you going for a family outing? If you can arrange a free weekend in the next month, I am thinking of going over myself to look at a few apartments - perhaps we could team up?