There are a few sites who sell the odd pin but to be honest eBay is far and away the best place to get DLRP pins - just make sure to search for all variations: DLRP Pins, Disney Paris Pins, Disneyland Paris Pins, Euro Disney Pins, Stitch Invasion etc... 99% of my non park bought pins have come from eBay.
There is an american site that I use which is http://www.pinfinder.com
It has thousands of different pins (mainly american) but it does have a DLRP section of pins (wayyyy at the bottom of the list). With the current £-$ exchange rate, they're not too bad.
You can buy direct from disney. try on the www.dizpins.com site there is the email address there. the other chance would be to buy on ebay for french seller . I have bought from the following and never had a trouble. planète JIM , bast912, in france and LLOYDYS-LOTS, in the UK.