It's a box lock. Typical Vouzelaud. Ornamental side plates with faux pins and tumbler axles. Well done, very high quality, but it's a BLE.
To get back to that gun . . . called the dealer and agreed on a price. Just picked it up yesterday. It is definitely a sidelock, but somewhat of a mystery gun. Original proofs are pretty obscure (other than the perron on the water table) but they're Belgian rather than French. The only French proofmark I can find on the gun is a crown over R--the open-style crown you see along with the standard PT French proofmark. Indicates reproof since 1960. But the gun is clearly marked "Vouzelaud" on the water table. I'm guessing it's a gun Vouzelaud either had made for them in Belgium, or else one they subsequently acquired and did a first class job of refurbishing.
