Based on the hilt decoration, the obvious owner crest, and what I can figure out from the blade inscription, you have an Officer's Model M1822 light cavalry sword. The manufacturer is Chatellerault. I can't make out the date of other than it is 18??. But it was made in January.
I have an Officer's M1822 made in 1844, it is a lighter sword than the enlisted men's versions. The enlisted model of sword was the basis for the American M1840 used in huge quantities during the American Civil war, and in the frontier period. I have a M1840 Ames from 1845 and it is for all intents and purposes, an exact copy of the French M1822 enlisted. The M1860 sword was "based" on the M1822. The M1860 was used in the American Civil through the frontier period, it is a light version of the M1822.
Still being made for the US in 1906
I am of the opinion the M1822 was one of the most successful military cavalry sword patterns ever made. The Turks had a version, the American's, did, South American countries copied it. The Germans made lots of M1840's for the American Civil war, don't know if they made any for themselves. I have a French M1822 that was made in the 1920's. It has an extraordinary service life for a sword. It is one of the great cavalry swords, well balanced, good for the thrust, good for the cut.
Now the hard part is finding who the original owner was. Good luck on that.
The American M1850 Infantry Officer sword was copied from the French pattern. French military swords were good designs, and were excellent for the purpose. This is a M1850 American Officer's sword, made by the French firm Klingenthal. This M1850 made to sell during the American Civil War.
It is my recollection that Confederate General JEB Stuart carried a French Officer Model M1822 during the American Civil War. Having either a French, or British sword, was quite the prestige item for an American Officer. They, like their European counterparts, had to buy their sidearms, which is why there are more Officer model swords around. The Officers took them home, while the weapons held by the military often ended up being demilled.