The French word "chasser", comes from German "jager" - hunter, chasseur. In the French army all regiments of light infantry were referred to as chasseurs.
The chasseurs went through sustained and tough training, considerably different from the training of line infantry. A minimum of time was spent on drilling, and a lot of efforts were applied to improve soldiers' marksmanship.
Compared to line infantry, the light infantry was supposed to be able to immediately break into small groups to create a long extended circuit of riflemen, and to be able to operate individually without waiting for direct command. They often moved an extended distance ahead of the army, firing at the enemy from long range, breaking its formations and demoralizing it.
Rather frequently they were used to fire at the enemy from buildings and other natural cover, or for fighting in forests and wilderness areas. The chasseurs received special objectives, including the elimination of enemy officers and standard-bearers and that of artillery crews prior to storming gun batteries.
Carabineer companies were established out of most skilled and accurate chasseurs to make elite units armed with rifled guns or as they were also called, carbines. A bullet fired from such a weapon rotated in flight, increasing the accuracy and distance of shot. On the downside though, it took longer to load than it did a smoothbore musket.