16 pagesNational audienceThis paper revisits the relation between proximity and interactions, in the light of new thoughts on the concepts of proximity. We start from the idea that proximity, in the most general sense, reflects the easiness to interact. It results that: (1) proximity can be expressed in terms of costs; (2) different forms of proximity correspond to different modes of interaction and to the associated costs. On the basis of these premises and of the various forms of the concept in the economics of proximity and in the economics of agglomeration, we suggest to deal with four forms of proximity, three of them closely linked to the economics of proximity, and one entirely new: virtual geographical proximity.Ce papier réexamine ...