I wanted to post what I got back on another forum. Seems to line up well with the comments here and thanks to all who took the time to respond it's such a great thing to see how many people in the world can still take the time to help someone out. I believe we've decided to keep this one in our personal collection. It's just such a nice gun!!
This is an Emile Warnant-made Belgian boxlock non-ejector made on the Anson and Deeley action with a Greener crossbolt and Anson pushrod forend release. It was made in 1924 for export to France. It is a 16-gauge with 2.5" chambers and both barrels choked (you will need to measure the degree of choke with a gauge, as Belgian guns of this time were notoriously sloppy in terms of choke measurements).
Important marks of note: "c" denotes the year 1924. This jives with all the other proof marks on the gun.
The curious thing is that the inspector's mark (* over P) belonged to an inspector who was active from 1952 to 1960. Not sure why it's there unless the gun was reproofed at some point.
* over EM is Emile Warnant's maker's hallmark.
"Siemens-Martin Steel" means the barrels are fluid steel and made using the open-hearth process
"La Chauguette A Lisieux" means "The Watchtower of Lisieux." Lisieux is a commune in Normandy, about midway between Caen and Rouen. It was the site of the first successful manned helicopter flight in 1907 by Paul Cornu. The town was mostly destroyed in 1944 when the Allied bombardment of Normandy started prior to the D-Day landings. Cornu and 799 other civilians were killed. I would expect "La Chauguette A Lisieux" to be the name of a sporting goods/gun shop in Lisieux. Warnant tended to make guns for others.
France has accepted Belgian proofs without the need to reprove for some time, but the formation of the CIP in 1914 means that the gun was not required to be reproved in any CIP participant country.
"Importe De Belgique" is French for "Imported from Belgium." Again, a Belgian gun that was made for sale in France.
Some information on Emile Warnant. The Warnant Family, by the way, was a storied firearms manufacturing family in Belgium. There are many examples of their various guns out there.
Emile Warnant:
Arms manufacturer
Known addresses
Rue Lamarck, 101 Liège (04/19/1907)
Rue de la Jonction, 13 Brussels (17/08/1911)
Rue Jonruelle, 66 Liège (28/12/1921)
Rue Lamarck, 99 Liège (Ann. 1924)
Filing patents in Belgium
No. 199506 – 19/04/1907 Shotgun ejector
No. 238160 – 17/08/1911 Safety device for automatic firearms
No. 239653 – 18/10/1911 Safety device for automatic firearms (brvt ppal No. 238160 of 17/08/1911)
No. 300835 – 28/12/1921 Improvements to firearms
Littlegun.be has two examples that are very similar to your gun here (3rd and 5th guns on the page):
https://littlegun.be/arme%20belge/artisans%20identifies%20t%20w/a%20warnant%20emile%20fr.htmAs for value, assuming there are no pits in the barrels or chambers or other issues, (Does it lock up tightly? Are the barrels on face?) I would put it in the $400 - $600 range if you're willing to sit on it until you find a buyer. It'll sell faster at a $300-$450 price point.