What concordance should we put on the adjective interesting? Similarly, if we mean a red pencil and a pencil (where both elements are red), do we make the adjective singular or plural (and again, with what word do we do it)? If colors are used as adjectives, they follow the general rule of French grammar, in accordance with the noun they describe. This general rule is that colors in French correspond to different sexes (feminine / masculine) and numbers (singular / plural). There are four cases that apply to color matching in French: in French, adjectives must match the noun they describe in GENDER (masculine/feminine) and number (singular/plural). In grammatical terms, the adaptation of the correct form of adjectives to the nouns they describe is called adjective overegage. .