Regulation Uniforms

The French army in 1812 were still wearing the blue, white and red uniform that replaced the Bourbon white uniform in 1793 (except for the Imperial Guard, they did their own thing). The basic ligne infantry uniform was described in the Etat Militaire de la République Française pour l'Année X as follows:

Blue coat with red piping and white lining, deeply cut away over the stomach to expose the vest

White square lapels piped red

Red collar and cuffs piped white

White vest and breeches

Yellow metal buttons

Long gaiters (black in winter and white in summer)

White cross belts

The only major change by the Russian campaign was the introduction of the shako in 1806.

Légere infantry uniforms had broadly similar uniforms, with the below difference:

Lapels, vest, cuffs and breeches were blue with white piping

Buttons were white metal

Lapels were pointed and coat-tails were shorter

Half gaiters (below the knee instead of over), usually with a lace border at the top.

Foot artillery uniforms were also similar to line infantry with the below exceptions:

Blue coat, square lapels, collar, cuffs and breeches piped red and with red lining

Long gaiters

Yellow buttons

There was a major uniform reform conducted in 1812 resulting in the so-called Bardin uniform, easily identifiable by the coat being cut longer and squarer in the front and covering the stomach, however very few (if any) units that went to Russia received this uniform.

In terms of depictions of the regulation uniforms, the Uniformenkunde by Richard Knötel is highly regarded - Line infantry is here (you want the 1808 uniform, but the difference with the Bardin uniform under 1812 is also shown); Legere is shown here though these are Carabiniers rather than Chasseurs, so they're wearing epaulettes rather than shoulder straps and bearskins instead of shakos. Foot artillery is weirdly seldom depicted in any source, but here is the guard artillery, which wore similar uiforms, barring the bearskins and epaulettes; the cuffs would also be blue with red piping

The Lienhart and Humbert book Les Uniformes de l'Armée Française: Recueil d'Ordonnances de 1690 a 1894 available here is also very good for showing regulation uniforms of France (book 5 on foreign uniforms is hot garbage and should be avoided). In particular you want line infantry, light infantry and artillery here

The Vernet-Lami plates are also very good and almost contemporary to the Napoleonic period

I'd also highly recommend the book Napoleon's Army 1807-1814: as depicted in the prints of Aaron Martinet by Guy Dempsey. The Martinet prints were contemporary with the Napoleonic period and compiled from primary sources. Dempsey is one of the best current authors on Napoleonic uniforms, especially with regards to picking out 19th century authors that were just making up uniforms ("I found a previously undiscovered manuscript, didn't show anyone and then lost it again" seems to occur disturbingly frequently). Some of the prints are available here

There's also the Weiland uniform plates from 1807-08 published in 1812 - another important primary source