@Hexalyse @candle The gendered adjective is present in all latin languages, not just french (and they follow the same rules). Also, some adjectives are invariable in gender in french (ex. "jaune").
The gender can sometimes tell you to which nouns the adjective qualify. For instance "les chemins et les routes sinueux" and "les chemins et les routes sinueuses" are both correct, but do not have the same meaning. Because of the gender rules, in the first case, the adjective "sinueux" applies to both nouns "chemin" and "route" while in the second case, the adjective only applies to the second noun.