Résumé:

I'll present a review of what is known about effective low-energy theory arising as a result of compactification of string theory down to 4 dimensions. In particular, I'll discuss why Calabi-Yau manifolds naturally arise as internal compactification manifolds, what is known in this case about quantum corrections, and why these manifolds are not enough from the phenomenological point of view. If time permits, I'll also present basic facts about flux compactifications allowing to get more realistic models.