[Closed] Secure car parking in Paris?

It's looking like our usual summer pilgrimage to the Alps is going to have a week's stop in Paris on the way there. Usually we drive over, so the current idea is to drive to Paris, leave the car there, then pick it up and drive on a week later.

The problem is that there will be at least 2 Downhill bikes in the back of the car, which we'd like to ensure we not tea-leaved before we get to ride them!

I've had a quick look already, but does anyone here have any experiences with secure places to park in, or around, Paris? If I get really lucky, I'll be able to use one of my work's car parks.... better get networking now though....

Cheers,
Mark