SUMMARY This is the third and last paper dealing with a survey of the geographical mobility of the French population, and of the motivations underlying such movement, whether they are ' removals ' in a limited area or ' migration ' over a longer distance. A categorisation of these motivations {economic of family reasons, housing conditions, personal convenience) leads to distinctions which have no real meaning. Movements cannot normally be accounted for by one reason alone. Spatial and social mobility are seen to be linked. Those remaining in the same social status group are the least mobile, whilst those socially upwardly mobile are also more mobile geographically. Spatial mobility appears as a corollary of geographical mobility and vice versa. In itself, geographical mobility is not viewed favourably by respondents, though they are willing to recognize that it may be beneficial for the individual. Movement, wich is seen as a trade off between economic demands and individual aspirations, is accepted, provided it permits the fulfilment of personal needs or ambitions.