I'm afraid I've never come across a site that presents the info your searching for other than specific nurseries in parts of Europe, and then the photos and descriptions tend to be pretty useless. Try and post some pics fairly sure one of us will be able to ID it for you....now if you wanted links to tropical plants/trees etc well.....
http://www.toptropicals.com/html/top...ry/gallery.htm
This site is about as comprehensive as you'll get but is limited to climates that could be described as tropical...South of France sure but not Paris.
If you have a few hours to spend and like looking at plant pics (I do) have a hunt around the various parts of the site its pretty big, try searching for a plant you know the name of flower colour etc, then see how you might use the site to find a plant for which you have only limited info.