The Montréal region is a source of concern to many. In their search for solutions over the past two decades, have those concerned considered the possibility that the problem has been posed correctly? Is it possible, for example, that the many "empty" spaces result less from urban sprawl than from structural factors? This is the hypothesis of this work. The identification of an abstract structure of locations which constrain settlement will call into question the policy of zoning, the main tool of urban planning. Zoning is not rejected, however. On the contrary, the study demonstrates its validity, provided that its use aims at protecting existing properties.