(For those who are not familiar with what "used to" in English means:)
Used to is a unique expression in English. Its form and function are similar to a modal (i.e., it gives extra information about the verb and is followed by a base verb). Used to shows that an action was performed repeatedly in the past, but is no longer performed in the present. It is commonly used when talking about long periods in the past (e.g., childhood, school years, past job, etc.)
I used to eat meat, but I don’t anymore. They used to study English every day in high school.
I looked up "used to" here: http://www.wordreference.com/enfr/used%20to , and one entry seems to say that you must use "Avant" plus the imparfait form of a verb (and also, it seems that you must use "maintenant" in your sentence, too):
He used to ride his bike, but now he drives. I didn't use to like this song, but it's growing on me!
Avant, il prenait son vélo ; maintenant, il conduit. Avant, je n'aimais pas cette chanson, mais maintentant, je commence à l'apprécier.
But I'm not sure how to find out on the Web whether this is the only way to translate "used to". Is this the only way? (And how could I try to find out on my own without asking here on stackexchange?)