How do I get a Sim card in Paris for my laptop.

Go to FNAC or an Orange store.

Thank you, we will give it a try.

why would one need a sim card for a laptop? (just curious)_

I believe the SIM card would be for 3G access.

All of the main providers offer data plans, tough none is particularly inexpensive. Perhaps the most popular is Orange´s Mobicarte but SFR and Bouygues have plans as well. Here is an explanation on how to use the Mobicarte with Internet Max:

http://prepaid-wireless-internet-acc...id=PGWJ_Za0mSC

Where does one insert a SIM into a laptop? Might the OP be looking instead for a wireless device that goes into a USB port?

I'm still confused - I don't think wither of my laptops have a space for a sim card?

PS and I can get wireless access because the laptops have it built in, not something I have to buy.

If you are in a place without wifi you can use (e.g., your computer recognizes six different wifi signals, but they are all locked), a USB key device (modem) from a cell phone provider gives you internet access via the phone system.
Here's an example:
http://reviews.cnet.com/modems/veriz...-33411169.html

Some laptops have 3G SIM card slot that enables them to access mobile internet/broadband.
Alternatively many mobile phones can be used as modem, which can be linked to laptop with a data cable or bluetooth (called tethering).
Unfortunately France is one of the more expensive countries for PAYG data access.

Thanks, Alec, you've explained why OP wants a SIM for a laptop; I have older laptops that lack the SIM slot so I just learned something new.