diff --git a/la_chariotte/order/migrations/0018_order_articles_nb.py b/la_chariotte/order/migrations/0018_order_articles_nb.py
new file mode 100644
index 0000000..01379d7
--- /dev/null
+++ b/la_chariotte/order/migrations/0018_order_articles_nb.py
@@ -0,0 +1,17 @@
+# Generated by Django 4.2 on 2023-05-12 14:38
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("order", "0017_orderauthor_alter_order_author"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="order",
+            name="articles_nb",
+            field=models.PositiveIntegerField(default=0),
+        ),
+    ]
diff --git a/la_chariotte/order/models.py b/la_chariotte/order/models.py
index c3d7e77..c9a1f19 100644
--- a/la_chariotte/order/models.py
+++ b/la_chariotte/order/models.py
@@ -78,6 +78,7 @@ class Order(models.Model):
         GroupedOrder, on_delete=models.CASCADE, related_name="order_set"
     )
     author = models.ForeignKey(OrderAuthor, on_delete=models.CASCADE)
+    articles_nb = models.PositiveIntegerField(default=0)
 
     def __str__(self):  # pragma: no cover
         return f"Commande de {self.author} pour la commande groupée {self.grouped_order.pk}"
diff --git a/la_chariotte/order/templates/order/grouped_order_detail.html b/la_chariotte/order/templates/order/grouped_order_detail.html
index 1fef291..cee5cd3 100644
--- a/la_chariotte/order/templates/order/grouped_order_detail.html
+++ b/la_chariotte/order/templates/order/grouped_order_detail.html
@@ -59,20 +59,21 @@
         {% endfor %}
       </tbody>
     </table>
+    {% if error_message %}<p class="has-text-danger">{{ error_message }}</p>{% endif %}
     <br>
     <p class="title">Vos informations</p>
     <div class="columns">
       <div class="column">
         <p><label for="first_name">Prénom : </label>
-        <input id="first_name" type="text" name="first_name" required></p>
+        <input id="first_name" type="text" name="first_name" placeholder="Votre prénom" required></p>
         <p><label for="first_name">Nom : </label>
-        <input id="last_name" type="text" name="last_name" required></p>
+        <input id="last_name" type="text" name="last_name" placeholder="Votre nom" required></p>
       </div>
       <div class="column">
         <p><label for="phone">Numéro de téléphone :</label>
-        <input id="phone" type="text" name="phone" required></p>
+        <input id="phone" type="text" placeholder="0601020304" name="phone" required></p>
         <p><label for="email">Adresse mail : </label>
-        <input id="email" type="text" name="email" required></p>
+        <input id="email" type="email" placeholder="exemple@mail.fr" name="email" required></p>
       </div>
     </div>
 
diff --git a/la_chariotte/order/templates/order/grouped_order_overview.html b/la_chariotte/order/templates/order/grouped_order_overview.html
index 6539404..08293a5 100644
--- a/la_chariotte/order/templates/order/grouped_order_overview.html
+++ b/la_chariotte/order/templates/order/grouped_order_overview.html
@@ -24,7 +24,7 @@
   <ul>
       {% for order in grouped_order.order_set.all %}
     <li>
-      {{ order }} : [prix total]
+      {{ order }} : {{ order.articles_nb }}
     </li>
     {% endfor %}
   </ul>
diff --git a/la_chariotte/order/tests/test_views.py b/la_chariotte/order/tests/test_views.py
index d7c7777..00d7d5e 100644
--- a/la_chariotte/order/tests/test_views.py
+++ b/la_chariotte/order/tests/test_views.py
@@ -262,6 +262,56 @@ class TestGroupedOrderDetailView:
         assert item2.ordered_nb == 1
         order = Order.objects.first()
         assert order.ordered_items.count() == 2
+        assert order.articles_nb == 5
+
+    def test_order_item__no_articles_ordered(self, client, other_user):
+        """
+        From the OrderDetailView, we order without having changed any item quantity.
+        An error is raised.
+        """
+        grouped_order = create_grouped_order(
+            days_before_delivery_date=5,
+            days_before_deadline=2,
+            name="gr order test",
+            orga_user=other_user,
+        )
+        item = Item.objects.create(
+            name="test item 1", grouped_order=grouped_order, price=1
+        )
+        detail_url = reverse(
+            "order:grouped_order_detail",
+            kwargs={
+                "pk": grouped_order.pk,
+            },
+        )
+        response = client.get(detail_url)
+        assert response.status_code == 200
+        assert "test item" in response.content.decode()
+        assert "gr order test" in response.content.decode()
+        assert item.ordered_nb == 0
+        order_url = reverse(
+            "order:order",
+            kwargs={
+                "grouped_order_id": grouped_order.pk,
+            },
+        )
+        response = client.post(
+            order_url,
+            {
+                f"quantity_{item.pk}": 0,
+                "first_name": "Prénom",
+                "last_name": "Nom",
+                "phone": "0645632569",
+                "email": "test@mail.fr",
+            },
+        )
+        order = Order.objects.first()
+        order.articles_nb == 0
+        assert response.status_code == 200
+        assert (
+            response.context["error_message"]
+            == "Veuillez commander au moins un produit"
+        )
 
 
 class TestGroupedOrderOverview:
diff --git a/la_chariotte/order/views.py b/la_chariotte/order/views.py
index 90fd1eb..3348de2 100644
--- a/la_chariotte/order/views.py
+++ b/la_chariotte/order/views.py
@@ -127,33 +127,31 @@ class ItemCreateView(UserPassesTestMixin, generic.CreateView):
 def order(request, grouped_order_id):
     """Creates an AnonymousUser, and an Order for this GroupedOrder, with related OrderedItems"""
     grouped_order = get_object_or_404(GroupedOrder, pk=grouped_order_id)
-    try:
-        # get a dict with (quantity_{{item_id}}:{{quantity}})
-        orders_dict = {
-            k: v for k, v in request.POST.items() if k.startswith("quantity")
-        }
-        first_name = request.POST["first_name"]
-        last_name = request.POST["last_name"]
-        phone = request.POST["phone"]
-        email = request.POST["email"]
-        # selected_item = grouped_order.item_set.get(pk=request.POST["item"])
-    except (KeyError, Item.DoesNotExist):
+    # get a dict with (quantity_{{item_id}}:{{quantity}})
+    orders_dict = {k: v for k, v in request.POST.items() if k.startswith("quantity")}
+    first_name = request.POST["first_name"]
+    last_name = request.POST["last_name"]
+    phone = request.POST["phone"]
+    email = request.POST["email"]
+    # selected_item = grouped_order.item_set.get(pk=request.POST["item"])
+    author = OrderAuthor.objects.create(first_name=first_name, last_name=last_name)
+    order = Order.objects.create(author=author, grouped_order=grouped_order)
+    for k, v in orders_dict.items():
+        item = grouped_order.item_set.get(pk=k.split("_")[1])
+        OrderedItem.objects.create(nb=v, order=order, item=item)
+        compute_ordered_nb(item)
+    compute_order_articles_nb(order)
+    if order.articles_nb == 0:
         # Redisplay the order form for this grouped order.
         return render(
             request,
             "order/grouped_order_detail.html",
             {
                 "grouped_order": grouped_order,
-                "error_message": "Veuillez remplir tous les champs",
+                "error_message": "Veuillez commander au moins un produit",
             },
         )
     else:
-        author = OrderAuthor.objects.create(first_name=first_name, last_name=last_name)
-        order = Order.objects.create(author=author, grouped_order=grouped_order)
-        for k, v in orders_dict.items():
-            item = grouped_order.item_set.get(pk=k.split("_")[1])
-            OrderedItem.objects.create(nb=v, order=order, item=item)
-            compute_ordered_nb(item)
         # Always return an HttpResponseRedirect after successfully dealing
         # with POST data. This prevents data from being posted twice if a
         # user hits the Back button.
@@ -169,3 +167,12 @@ def compute_ordered_nb(item):
         ordered_nb += order.nb
     item.ordered_nb = ordered_nb
     item.save()
+
+
+def compute_order_articles_nb(order):
+    """Computes the number of articles in a given order"""
+    articles_nb = 0
+    for ord_item in order.ordered_items.all():
+        articles_nb += ord_item.nb
+    order.articles_nb = articles_nb
+    order.save()