Manufrance was a French mail order outfit. They didn't make anything so yes, just a private labelled Unique I believe.

Frank

 

I searched google for hours and can not find this gun ... im usually fairly good at finding things but this one has proven to be difficult

 

Reading about manufrance kinda seems they were frances jc higgins .... made by someone else branded by them

 

I had several Unique 22 pistols. The 52s were one of my favorites. They made a version that you could morph pistol into a carbine. I traded them off, the beater looking one in pics I carried several years while I was wade fishing.

 

I may be repeating what you already know, but Unique Arms of France made several variations of the model d with the main difference being the length of the barrel. Only the Model D-2 (or maybe it was the D-3) was sold in the US under the names JC Higgins Model 85 and Western Field Model 5. I have a 6" barrel that came off of I think a D-4. I have never heard of MANUFRANCE ST ETIENNE but if Unique Arms made pistols for Sears and Wards it makes sense that they have have done the same with french brands. Strange though that Unique isn't on gun somewhere. If you would post pictures, it might help. I have a manual somewhere that shows all of the D variations, plus you can get a repo on eBay for less than $10.
DDM