You can get them on Ebay in the religious collectible section, on Ruby Lane, or on Etsy but be prepared to pay a nice sum for them if they're not the simple more modern ones. There are blue enamels out there from 50's and later that aren't nearly as expensive, but they tend to be bigger while the little antique French ones are about the size of a dime. They're much more ornate. The enamel work is just gorgeous. That type of enamel work on silver religious medals was done mostly from the late 1800's through the 1940's and the French ones were the best I think. They look like this. This is actually quite a simple one. Probably 1920's. Looks Art Deco. They come with all sorts of enameled flowers and such sometimes. I'll try to find my little box of them and take a pic of some of them so you can really see. I have much more intricate ones that this.
http://www.etsy.com/listing/102305042/a ... a_includes[]=materials&ga_search_query=antique+blue+enamel+religious+medals&ga_search_type=all&ga_view_type=gallery
Actually they've gone up since I looked last if that's not an inflated price on that one. I have about 50 of them at the moment. I bought a nice lot from a woman here a few years ago at an Estate sale. I also bought a huge lot of art deco holy cards from her, some antique rosaries. I tried to tell her she was sitting on a little goldmine with that stuff but she didn't want to hear it. I bought it all with intent to sell. I have a few I'm keeping for sentimental reasons but not those. I've been planning a little store for this stuff for a long time. My late aunt used to also collect it in a big way. The medals I am keeping are hers. I inherited a lot of her stuff when she died and she used to tell me a lot about it. She was a font of information on it all actually.
Dolls too. Some of my dolls were hers actually. I got them when she died too. Nobody in my family had a clue as to what that stuff was worth so they just handed it off to me as per her request. Nobody even quibbled about any of it when she died even though it was worth a nice sum her collections. But she always made sure I knew. When I was growing up my parents they just thought she was the world's greatest pack rat and that it was all "junk" all her various collections. Little did they know, laugh. She collected dolls, religious stuff, old clothes and hats, costume jewelry but she had a good eye. Most of it has real worth in today's collectibles market.
I have a website/blog that I am working on where I mean to display my photography, talk about and sell stuff like this. I'm also looking into a store online on Etsy or Amazon. I don't really want to mess with Ebay or Ruby Lane. Too expensive. I like Etsy I think but what I really want is my own store site with my own shopping cart et all. FYI, they don't say sterling on them usually but they mostly are. Occasionally you'll see them with a maker's mark but that's rare.