Don't know about cable - never heard of it where I am (Valbonne, 5km from Antibes, 7km from Cannes) - you'll need ADSL but make sure you are in an area where it is available. I use Wanadoo (FT ISP) not the cheapest but very reliable.
For Bloomberg and CNBC get Sky Digital (also gives you all the UK terrestial channels and all the footy). Many apartment blocks have comunal dish or just fire one up on the balcony yourself - I know loads of people doing this.
One point - the electricity supply is NOT reliable - far more power cuts than UK and be extra careful when there are storms around - I've lost 3 satellite decoders, 2 modems and a video recorder. Also had the fuse-box fried!
Surge protectors are not always good enough and a UPS is essential.
Tax? Can't help you on that one - I have a 'real' job which pays the social charges - I've only been trading a year and just breaking even so I'm not too worried about tax just yet. It's true that wives and kids greatly reduce your tax bill - check the previous links.
There are some 'straight' advisors here who will help you but plenty of gangsters too.
Re publications - Playboy no problem, the rest could be tough although you should be able to order them through your local newsagent.
Concerning 500E's a month rent on the coast? Careful - for that money it will be small (1 bed or T2 as they call them here) and in the back of the town - 700 is more realistic for a nice 1 bed place. Better deals inland a few K's. Also remember you must give 2 months rent as deposit and you have to pay the agency fees (usually about 80% of 1 months rent). Also most places are unfurnished.
Here's a link to the local free-ads paper for the Riviera which gives you a rough idea:
http://www.le06.fr
PM me if you need more info.
Hope this helps.