The coat pictured is about five shades darker than the French blue RJ Classics I used to have, which I loved to bits and wore everywhere. I think the color of the coat you linked to is probably appropriate than that of my old coat. It's beautiful!
I have that exact coat, except with a lilac lining. It was approved by my fairly traditional, conservative trainer. I even wore it & pinned in some eq classes at an A show earlier this summer. It looks fabulous with a white or light lavendar shirt. I actually got compliments on it from another trainer that I didn't know. Go for it!
I've been coveting one for a while now. It's a nice alternative to the dark navy blue that everybody is wearing right now, and a great way to subtly stand out. A black coat just wouldn't look great on my horse (she's like TheOrangeOne's horse but a little darker). Plus, it looks really retro! Like rust breeches, but more attractive.
If I remember correctly someone else posted some pics of themselves in that exact coat and it was actually much lighter in person than on the website, like the second photo that pony + an inch posted. If this is your second coat I would say go for it but as a main coat you may want to get something darker. I've been coveting that coat for awhile now
My daughter has a French blue jacket with a caramel coloured lining and piping on the collar. It made it easy to find her in the warm up ring when most other jackets were navy or dark grey! (didn't hurt in the hack either)
That's not really the color I think of when I hear "French blue", but it's lovely
My most favorite coat ever when I was young was a beautiful blue (a tad darker than Little Indian's) that looked abfab with my seal brown TB mare