A study of telephone interaction rounds out our knowledge of the French population's sociability, the analysis of which has hitherto been limited to face-to-face interactions. Telephone sociability is found to be more restricted and less diverse than face-to-face sociability. The telephone is used in such a way as to maintain only a core of close friends from among the circle of social contacts. Contrary to all expectations, the geographic concentration of telephone contacts is almost as high as that for the other contacts: half live less than ten kilometres away. The frequency of telephone contact is a less partial indicator of the quality of a social link than the frequency of face-to-face encounters. Firstly, the telephone link reinforces the face-to-face link (the more you see people, the more you call them). Secondly, the telephone can also replace face-to-face contact, especially in the case of close family often called for long periods of time when they cannot be visited because they live too far away. The telephone link contributes to social integration in cases of solitude or isolation from face-to-face contact. The telephone plays a compensatory role. The social groups that spend the most time on the telephone are those at risk of more fragile face-to-face relationships (people living alone or without work). Lastly, the telephone increases a strong pre-existent integration. This is especially the case for people with a high level of education, whose telephone use covers a wide and diverse network of contacts (extensive use) and adds to other, highly intensive forms of sociability.