This is what I know:
I have a Harmonia Bassoon, Made in Paris. It is made of maple, with 4 thumb keys on the tenor joint, and it's really old. It plays great, but I don't know much about it or the company who made it. It is serial number 52.

If anyone knows anything useful about the maker, etc, please post here.
Thanks very much!

The bassoon is listed for sale on Ebay: item number 230520194297. There are pictures, and it's really reasonably priced, for any who would like to see it as well.

Thanks for your interest!

Does it actually say 'Made in Paris' or is it just Harmonia, Paris?

The only French maker of German system bassoons I've heard of is Cabart who made some in the 1940s which weren't very successful.

My guess is that Harmonia was just a company who bought instruments stamped with their own name from a company in Germany like Kohlert or Schreiber.

I've had a look at the ebay pic and it's a Cabart, as contra448 thought. Cabart are the only bassoon I know of that has a roller on the low B key as standard.Also Cabart had a serrated whisper key touchpiece which is unusual.

Alright, well thanks very much for the information. It does play very well, and I have gotten a lot of enjoyment when I've had the opportunity to play it. I'm honestly a little surprised by how old it probably is, but when I've owned it I've taken very good care of it. I hope the person who buys it on Ebay likes it as much as I have!