The concept of corpus presents several challenges in linguistics: what is a corpus ? How is it designed ? How is it used and analysed ? This paper aims at providing lines of thinking around these issues. Corpus linguistics has been partially inspired by foreign language teaching, with people like Sweet or Palmer and then by Firth, Sinclair or Halliday. Accordingly, the use corpora in the field of foreign language teaching seems to be relevant. In this paper, we look back on the choices that have been made in the design of the IntUne corpus (a media corpus collected in a project of the sixth framework programme of the European Union) and on the theoretical perspective which motivated them by making a distinction between linguistique de corpus and linguistique sur corpus. In a second part, we shall describe an experimentation of the use of the IntUne corpus within a course entitled "Didactic of French as a foreign language", which took place at the University of Brittany, Lorient.