diff --git a/lib/tasks/deployment/20200414104712_split_geo_area_selection_multipolygons.rake b/lib/tasks/deployment/20200414104712_split_geo_area_selection_multipolygons.rake
new file mode 100644
index 000000000..930a650aa
--- /dev/null
+++ b/lib/tasks/deployment/20200414104712_split_geo_area_selection_multipolygons.rake
@@ -0,0 +1,18 @@
+namespace :after_party do
+  desc 'Deployment task: split_geo_area_selection_multipolygons'
+  task split_geo_area_selection_multipolygons: :environment do
+    puts "Running deploy task 'split_geo_area_selection_multipolygons'"
+
+    Champs::CarteChamp.where.not(value: ['', '[]']).includes(:geo_areas).find_each do |champ|
+      if champ.send(:selection_utilisateur_legacy?)
+        legacy_selection_utilisateur = champ.selections_utilisateur.first
+        champ.send(:legacy_selections_utilisateur).each do |area|
+          champ.geo_areas << area
+        end
+        legacy_selection_utilisateur.destroy
+      end
+    end
+
+    AfterParty::TaskRecord.create version: '20200414104712'
+  end
+end