In five chapters, this thesis traces the question of humanity in the thought of the French philosopher Emmanuel Lévinas, mainly in his works De l'évasion (1935), De l'existence à l'existant (1947), Totalité et infini (1961) and Éthique comme philosophie première (1982), which represent various stages of his philosophical development. It offers an exposition of Lévinas's most original concepts, follows their development and sketches their parallel and/or polemic concepts in the European thought, placing them within the context of Lévinas's life-work. For Lévinas, the question of humanity appears as a transpostition of the question of God, who can not become an object of rational inquiry. In conclusion, the question of humanity becomes the theological issue par excellence. This study tries to show how theology can draw inspiration from Lévinas's concepts in various manners: (1) methodology: Lévinas shows what happens to our thought when we follow the principle Sein-lassen in questionning God and when we take this principle as a basis of our theological research; (2) re-thinking: Lévinas offers a critical revision of traditional theological concepts and endows them with existential meaning, (3) marginalized phenomena: Lévinas thoroughly analyzes phenomena, which has been neglected or marginalized by the...