Enkelvoud en meervoud

http://french.about.com/library/begin/bl_nouns2.htm
French Gender and NumberGenre et Nombre
Nearly all French nouns have different forms for singular and plural. In addition, many nouns that refer to people have both a masculine and a feminine form. Many of the rules here also apply to adjectives.
Note that the gender rules apply only to people and some animals. They do not apply to objects, which have a masculine or a feminine form, never both - learn more.
VI. Compound nouns

French Gender Lessons
French Plural/Number Lessons
French Parts of Speech