Gitane SS conversion - BB

HI all !
I've been posting on a couple of threads about a project I'm taking on. I was recently given a vintage Gitane racing bike, and crudely converted it to SS by removing the derailleurs and shifters and shortening th echain, just to get used to it. Vut I plan to change quite a bit more. Living in France and owning a french bike, I'm 99% sure it's a french BB. From what I gather, no-one makes cranks that'll fit this sort of BB any more (I'm lost when it comes to telling the difference between them, what difference they make in the chain line, how you get a good chain line etc etc.).
But I found this on a thread : http://www.velo-orange.com/grcrufrthbob.html
So would one of these fit with some pake cranks ? (http://tinyurl.com/lhglwz)
Do I need anything else to fit cranks onto a BB ? a seperate lockring or anything ?
How do I know what "size" BB i need ? What does that relate to ?
And what tools will I need to do this ? (excuse the "slight" stupidity of the questions, but I've only really got into bikes in the last couple of months, and this is my first project...)

Thanks !

Got a gitane myself, leaving it geared!

Utfs.
Last time I checked, both SJS and Spa Cycles had some French threaded BBs.
Would certainly be cheaper than shipping from VO.

Read this, then ask again; http://www.sheldonbrown.com/

Sorry... I feel a right tw@t now... From What Sheldon Brown says, and eBay, I'm guessing I'm searching for a french threaded ,square tapered, bottom bracket ? I don't have the correct tools to dismantle the BB, so i sthere a possibility that it would be italian threaded ? As SB says some high end French have Italian threads. I don't know if my bike would be considered as "high-end" though, so will have to wait until I get the required tools...
What **makes **a bike "high-end" ? the Groupset (Huret) ? The frame (Reynolds 531) ?...

It may be Italian threaded, but would probably have a 70mm (not 68) BB shell if it is.
I'd have thought that a Huret groupset would suggest French threads.
Get the BB out and it will be easy to determine which it is.
Are there any makings on it at all, make etc.?

I have a gitane with higher spec tubing than 531, it is all french threaded. A 60's one i think. I got a bb from the bicycle workshop in londons famous london.

does 510232 mean anything...?
I can't seem to find any French threaded BBs on SJS or spa cylces...:'( Only Italians...

though I may just be searching REALLY badly

the BB's out, and I now know it's french threading... Thanks for the help =)