1. Agreement:
* Gender: Adjectives agree in gender with the noun they modify. This means they have masculine and feminine forms.
* Number: Adjectives also agree in number with the noun. They have singular and plural forms.
Example:
* Masculine singular: _un livre beau_ (a beautiful book)
* Feminine singular: _une maison belle_ (a beautiful house)
* Masculine plural: _des livres beaux_ (beautiful books)
* Feminine plural: _des maisons belles_ (beautiful houses)
2. Placement:
* Descriptive adjectives usually come after the noun: _un livre intéressant_ (an interesting book)
* Possessive adjectives (my, your, his, etc.) come before the noun: _mon livre_ (my book)
* Demonstrative adjectives (this, that, these, those) come before the noun: _cette maison_ (this house)
* Indefinite adjectives (some, any, many, etc.) usually come after the noun: _des livres intéressants_ (some interesting books)
3. Irregular Forms:
Some adjectives have irregular forms:
* Beau/Belle: (beautiful) becomes beaux/belles in the plural
* Grand/Grande: (big, large) becomes grands/grandes in the plural
* Bon/Bonne: (good) becomes bons/bonnes in the plural
* Nouveau/Nouvelle: (new) becomes nouveaux/nouvelles in the plural
4. Special Cases:
* Adjectives of nationality: often end in "-ais" (e.g., _français_) and don't change for gender or number.
* Adjectives of color: usually don't change for gender or number (e.g., _rouge, vert_).
* Some adjectives don't change at all: (e.g., _unique, formidable_).
5. Comparison:
* Comparative: _plus_ + adjective + _que_ (more... than)
* Superlative: _le/la/les plus_ + adjective + _de_ (the most... of)
Examples:
* _Ce livre est plus intéressant que celui-là._ (This book is more interesting than that one.)
* _C'est la plus belle maison du quartier._ (It's the most beautiful house in the neighborhood.)
Remember: There are exceptions and nuances to these rules. It's best to learn the specific rules for each adjective as you encounter them.
Resources for learning more:
* Grammar books and websites dedicated to French grammar
* French language dictionaries (which often provide information on adjective agreement)
* Practice exercises to solidify your understanding of adjective usage