In French, the rules for capitalizing nationalities
are similar to those in English,
but there are some important distinctions.
Here's a breakdown:

Nationalities that function as proper nouns
(when they refer to specific people or groups)
are capitalized.
For example:

• Les Frangais (the French people)
• Les Américains (the Americans)

When nationalities are used as adjectives,
they are generally not capitalized.
For example:

• un vin frangais (a French wine)
• une cuisine italienne (an Italian cuisine)

Capitalize nationalities when they are used as nouns
to refer to specific groups of people or citizens
(e.g., “Les Canadiens”).

Do not capitalize them when used as adjectives
(e.g., “un produit chinois”).
This distinction is important to keep in mind while writing in French
to maintain correct grammatical conventions!