diff --git a/app/models/type_de_champ.rb b/app/models/type_de_champ.rb
index 11615ddd5..b979fdf45 100644
--- a/app/models/type_de_champ.rb
+++ b/app/models/type_de_champ.rb
@@ -785,7 +785,7 @@ class TypeDeChamp < ApplicationRecord
     when ['integer_number', 'decimal_number'], # recast numbers automatically
       ['decimal_number', 'integer_number'], # may lose some data, but who cares ?
       ['text', 'textarea'], # allow short text to long text
-      # ['drop_down_list', 'multiple_drop_down_list'], # single list can become multi
+      ['drop_down_list', 'multiple_drop_down_list'], # single list can become multi
       ['date', 'datetime'], # date <=> datetime
       ['datetime', 'date'] # may lose some data, but who cares ?
       true
diff --git a/spec/models/type_de_champ_spec.rb b/spec/models/type_de_champ_spec.rb
index a0481a31e..605ddb961 100644
--- a/spec/models/type_de_champ_spec.rb
+++ b/spec/models/type_de_champ_spec.rb
@@ -413,4 +413,66 @@ describe TypeDeChamp do
       end
     end
   end
+
+  describe 'champ_value with cast' do
+    let(:procedure) { create(:procedure, types_de_champ_public: [{ type: type_champ }]) }
+    let(:dossier) { create(:dossier, procedure:) }
+    let(:type_champ) { :text }
+    let(:last_write_type_champ) { :text }
+    let(:champ_value) { 'hello' }
+    let(:champ_type) { TypeDeChamp.type_champ_to_champ_class_name(last_write_type_champ.to_s) }
+    let(:type_de_champ) { procedure.active_revision.types_de_champ.first }
+    let(:champ) { dossier.champs.first }
+
+    subject { champ.update_columns(type: champ_type, value: champ_value); type_de_champ.champ_value(champ) }
+
+    it { expect(subject).to eq('hello') }
+
+    context 'text -> integer_number' do
+      let(:last_write_type_champ) { :text }
+      let(:type_champ) { :integer_number }
+
+      it { expect(subject).to eq('') }
+    end
+
+    context 'integer_number -> text' do
+      let(:last_write_type_champ) { :integer_number }
+      let(:type_champ) { :text }
+      let(:champ_value) { '42' }
+
+      it { expect(subject).to eq('') }
+    end
+
+    context 'integer_number -> decimal_number' do
+      let(:last_write_type_champ) { :integer_number }
+      let(:type_champ) { :decimal_number }
+      let(:champ_value) { '42' }
+
+      it { expect(subject).to eq('42') }
+    end
+
+    context 'decimal_number -> integer_number' do
+      let(:last_write_type_champ) { :decimal_number }
+      let(:type_champ) { :integer_number }
+      let(:champ_value) { '42.1' }
+
+      it { expect(subject).to eq('42.1') }
+    end
+
+    context 'drop_down_list -> multiple_drop_down_list' do
+      let(:last_write_type_champ) { :drop_down_list }
+      let(:type_champ) { :multiple_drop_down_list }
+      let(:champ_value) { type_de_champ.drop_down_options.first }
+
+      it { expect(subject).to eq(champ_value) }
+    end
+
+    context 'multiple_drop_down_list -> drop_down_list' do
+      let(:last_write_type_champ) { :multiple_drop_down_list }
+      let(:type_champ) { :drop_down_list }
+      let(:champ_value) { "[\"#{type_de_champ.drop_down_options.first}\"]" }
+
+      it { expect(subject).to eq('') }
+    end
+  end
 end