The study of territorial planning in the region of Occitanie sheds light on two contemporary questions. What becomes of this policy once regions enjoy significant powers in the field? How can regions carry out this policy in a field strongly structured by two powerful metropolitan cities (Toulouse and Montpellier)? Historical study of the fusion of the pre-existing regions Midi-Pyrénées and Languedoc-Roussillon highlight the importance territorial representation at the origin of territorial planning. It shows also the importance of compromises established between the political culture of the two regions, between the regions and the metropolitan cites, and finally between territorial planning and various sectoral policies. Our principal finding is that the regions’ power of territorial planning is effective only to the extent that it is shared with the metropolitan cities, who in practice expand their area of influence.