Why is it 'au cinema' and not 'a le cinema' in French?

French contracts the prepositions a and de with the masculine and plural definite articles. A + le becomes au (au cinema), a + les becomes aux (aux enfants), de + le becomes du (la maison du voisin), and de + les becomes des (les jouets des enfants). The contractions are mandatory. They only apply to le and les; a la and a l' stay as they are (a la piscine, a l'ecole).

When do I use 'a' versus 'en' for a country?

Countries take en when they're feminine or start with a vowel (en France, en Italie, en Iran), and au when they're masculine and start with a consonant (au Japon, au Canada, au Portugal). Plural country names take aux (aux Etats-Unis, aux Pays-Bas). For cities, always use a (a Paris, a Madrid, a Tokyo). The same prepositions cover both 'in' and 'to' - 'je vais en France' (I'm going to France) and 'j'habite en France' (I live in France) use the same en.

French Prepositions

A small set of prepositions does most of the work in French. This page covers the eight you need at Foundation tier and the two grammar rules that govern them.

The core eight

Preposition	Core meaning	Example
a	to, at	je vais a Paris
de	of, from	je viens de Londres
en	in, by (transport)	en France, en train
dans	in (inside)	dans la maison
sur	on	sur la table
sous	under	sous le lit
chez	at someone's (house)	chez moi, chez le docteur
avec	with	avec mes amis

The basics. A and de carry the most semantic weight and the most grammar (the contractions), so they get their own section below.

The mandatory contractions

When a or de meets the masculine singular definite article le or the plural definite article les, they contract. The contractions are required, not optional.

a + le = au: au cinema, au restaurant, au parc
a + les = aux: aux enfants, aux Etats-Unis, aux marches
de + le = du: la fin du film, la maison du voisin
de + les = des: les jouets des enfants, les chambres des hotels

The contractions only apply to le and les. A la, a l', de la, de l' stay as they are:

a la piscine (to the pool)
a l'ecole (at school)
de la cuisine (of the kitchen)
de l'eau (of water)

Note that du and des here are preposition + article, the same form as the partitive du / des but a different function. Context disambiguates.

a vs en with places

The rule for places is fiddly but firm.

Cities: always a.

a Paris, a Madrid, a Tokyo, a Londres

Countries: en for feminine countries and countries starting with a vowel, au for masculine-consonant countries, aux for plurals.

en France, en Italie, en Espagne, en Iran, en Inde (feminine or vowel)
au Japon, au Canada, au Portugal, au Mexique (masculine + consonant)
aux Etats-Unis, aux Pays-Bas, aux Philippines (plural)

Most country names ending in -e are feminine (la France, l'Italie). The big exceptions are le Mexique, le Mozambique, le Cambodge, le Zaire - masculine despite the -e.

The same prepositions cover both "in" and "to". Je vais en France (I'm going to France) and j'habite en France (I live in France) use the same en.

"From" with countries and cities

For "from", use de with feminine countries and cities, du with masculine countries, des with plural countries.

Je viens de Paris. (I'm from Paris.)
Je viens de France. (I'm from France - feminine.)
Je viens du Japon. (I'm from Japan.)
Je viens des Etats-Unis. (I'm from the US.)

The contraction rule is the same as everywhere else.

en vs dans

Both translate roughly as "in", but they cover different ground.

en is mostly idiomatic and indefinite: en France, en train, en vacances, en hiver.
dans is concrete and points to a specific container: dans la maison, dans la voiture, dans la boite.

A useful rule of thumb: en doesn't take an article after it (en France, not "en la France"); dans does (dans la voiture, dans le jardin).

chez

Chez is the prepositional shortcut English doesn't have. It means "at the place of" - someone's home, a shop owned by them, a profession's premises.

chez moi (at my place / at home)
chez Marie (at Marie's)
chez le docteur (at the doctor's)
chez le coiffeur (at the hairdresser's)
chez nous (at our place; also: in our country / culture)

Always followed by a person (name, pronoun, profession). Never followed by a building noun - chez l'hopital is wrong; the right form is a l'hopital.

Worked examples

Je vais au cinema avec mes amis. (I'm going to the cinema with my friends.)
Elle habite a Paris depuis dix ans. (She has been living in Paris for ten years.)
Le livre est sur la table dans la cuisine. (The book is on the table in the kitchen.)
Mes parents viennent du Portugal. (My parents are from Portugal.)
Demain je vais chez le docteur. (Tomorrow I'm going to the doctor's.)
En ete, nous partons en vacances en Italie. (In summer, we go on holiday to Italy.)

Common mistakes English speakers make

Writing a le or de le when the rule forces au or du: je vais a le cinema is wrong, it's je vais au cinema. Using dans instead of en for countries: dans la France is wrong, it's en France. And translating "at the doctor's" with a instead of chez: a le docteur is wrong on two counts (it should be both chez and contracted to au if it were a location).