diff --git a/core/management/commands/populate.py b/core/management/commands/populate.py
index 09ec8180..de803d66 100644
--- a/core/management/commands/populate.py
+++ b/core/management/commands/populate.py
@@ -252,7 +252,7 @@ class Command(BaseCommand):
             date_of_birth="1942-06-12",
             password="plop",
         )
-        User.objects.all().update(cgu_approved=True)
+        User.objects.all().update(cgu_approved_at=now())
         User.groups.through.objects.bulk_create(
             [
                 User.groups.through(group=groups.counter_admin, user=counter),
diff --git a/core/migrations/0051_user_eula_approved.py b/core/migrations/0051_user_cgu_approved_at.py
similarity index 59%
rename from core/migrations/0051_user_eula_approved.py
rename to core/migrations/0051_user_cgu_approved_at.py
index 6264436a..730b3225 100644
--- a/core/migrations/0051_user_eula_approved.py
+++ b/core/migrations/0051_user_cgu_approved_at.py
@@ -1,4 +1,4 @@
-# Generated by Django 5.2.17 on 2026-09-15 11:02
+# Generated by Django 5.2.17 on 2026-09-25 12:26
 
 from django.db import migrations, models
 
@@ -9,7 +9,7 @@ class Migration(migrations.Migration):
     operations = [
         migrations.AddField(
             model_name="user",
-            name="cgu_approved",
-            field=models.BooleanField(default=False, verbose_name="ToS approved"),
+            name="cgu_approved_at",
+            field=models.DateTimeField(null=True, verbose_name="ToS approved at"),
         ),
     ]
diff --git a/core/models.py b/core/models.py
index 148bda9a..8b057a03 100644
--- a/core/models.py
+++ b/core/models.py
@@ -44,6 +44,7 @@ from django.core.files.base import ContentFile
 from django.core.mail import send_mail
 from django.db import models, transaction
 from django.db.models import Exists, F, OuterRef, Q
+from django.db.models.aggregates import Max
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.functional import cached_property
@@ -291,7 +292,7 @@ class User(AbstractUser):
         ),
         blank=True,
     )
-    cgu_approved = models.BooleanField(_("ToS approved"), default=False)
+    cgu_approved_at = models.DateTimeField(_("ToS approved at"), null=True, blank=False)
     godfathers = models.ManyToManyField("User", related_name="godchildren", blank=True)
 
     objects = CustomUserManager()
@@ -419,6 +420,14 @@ class User(AbstractUser):
         )
         return age
 
+    @cached_property
+    def approved_current_cgu(self) -> bool:
+        qs = PageRev.objects.filter(page___full_name=settings.SITH_CGU_PAGE)
+        return (
+            self.cgu_approved_at is not None
+            and self.cgu_approved_at > qs.aggregate(date=Max("date"))["date"]
+        )
+
     def make_home(self):
         if self.home is None:
             home_root = SithFile.objects.filter(parent=None, name="users").first()
diff --git a/core/templates/core/cgu_approve.jinja b/core/templates/core/cgu_approve.jinja
index a152ef27..c683c799 100644
--- a/core/templates/core/cgu_approve.jinja
+++ b/core/templates/core/cgu_approve.jinja
@@ -27,9 +27,9 @@
       {% endtrans %}
     </div>
     <div class="form-group">
-      {{ form.cgu_approved.errors }}
-      {{ form.cgu_approved }}
-      {{ form.cgu_approved.label_tag() }}
+      {{ form.cgu_approved_at.errors }}
+      {{ form.cgu_approved_at }}
+      {{ form.cgu_approved_at.label_tag() }}
     </div>
 
     <input type="hidden" name="next" value="{{ next }}">
diff --git a/core/templates/core/register.jinja b/core/templates/core/register.jinja
index de97524e..91ad54e5 100644
--- a/core/templates/core/register.jinja
+++ b/core/templates/core/register.jinja
@@ -19,15 +19,15 @@
     {% csrf_token %}
     {% render_honeypot_field %}
     {% for field in form %}
-      {% if field.name not in ["cgu_approved", "captcha"] %}
+      {% if field.name not in ["cgu_approved_at", "captcha"] %}
         <div>{{ field.as_field_group() }}</div>
       {% endif %}
     {% endfor %}
     <div class="captcha">{{ form.captcha.as_field_group() }}</div>
     <div class="form-group">
-      {{ form.cgu_approved.errors }}
-      {{ form.cgu_approved }}
-      {{ form.cgu_approved.label_tag() }}
+      {{ form.cgu_approved_at.errors }}
+      {{ form.cgu_approved_at }}
+      {{ form.cgu_approved_at.label_tag() }}
     </div>
     <input type="submit" class="btn btn-blue" value="{% trans %}Register{% endtrans %}" />
   </form>
diff --git a/core/tests/test_core.py b/core/tests/test_core.py
index deb23f74..8395e8a6 100644
--- a/core/tests/test_core.py
+++ b/core/tests/test_core.py
@@ -27,6 +27,7 @@ from django.core.exceptions import ValidationError
 from django.core.mail import EmailMessage
 from django.test import Client, RequestFactory, TestCase
 from django.urls import reverse
+from django.utils.timezone import now
 from django.views.generic import View
 from django.views.generic.base import ContextMixin
 from model_bakery import baker
@@ -55,7 +56,7 @@ class TestUserRegistration:
             "password2": "plop",
             "captcha_0": "dummy-value",
             "captcha_1": "PASSED",
-            "cgu_approved": True,
+            "cgu_approved_at": now(),
         }
 
     @pytest.fixture()
@@ -94,7 +95,7 @@ class TestUserRegistration:
             ({"last_name": ""}, "Ce champ est obligatoire."),
             ({"captcha_1": "WRONG_CAPTCHA"}, "CAPTCHA invalide"),
             (
-                {"cgu_approved": ""},
+                {"cgu_approved_at": False},
                 "Vous devez approuver les conditions générales d'utilisation",
             ),
         ],
@@ -155,7 +156,7 @@ class TestUserRegistration:
 class TestUserLogin:
     @pytest.fixture()
     def user(self) -> User:
-        return baker.make(User, password=make_password("plop"), cgu_approved=True)
+        return baker.make(User, password=make_password("plop"), cgu_approved_at=now())
 
     @pytest.mark.parametrize(
         "identifier_getter",
@@ -203,7 +204,7 @@ class TestUserLogin:
 @pytest.mark.django_db
 class TestCGU:
     def test_cgu_approval(self, client: Client):
-        user = baker.make(User, password=make_password("plop"), cgu_approved=False)
+        user = baker.make(User, password=make_password("plop"), cgu_approved_at=None)
         user_url = user.get_absolute_url()
         res = client.post(
             reverse("core:login"),
@@ -211,11 +212,11 @@ class TestCGU:
         )
         assertRedirects(res, reverse("core:approve_cgu", query={"next": user_url}))
         res = client.post(
-            reverse("core:approve_cgu"), {"cgu_approved": True, "next": user_url}
+            reverse("core:approve_cgu"), {"cgu_approved_at": now(), "next": user_url}
         )
         assertRedirects(res, user_url)
         user.refresh_from_db()
-        assert user.cgu_approved
+        assert user.cgu_approved_at is not None
 
     def test_access_cgu_when_already_approved(self, client: Client):
         url = reverse("core:approve_cgu")
@@ -223,10 +224,10 @@ class TestCGU:
         res = client.get(url)
         assertRedirects(res, reverse("core:login"))
 
-        client.force_login(baker.make(User, cgu_approved=True))
+        client.force_login(baker.make(User, cgu_approved_at=now()))
         res = client.get(url)
         assertRedirects(res, settings.LOGIN_REDIRECT_URL)
-        res = client.post(url, {"cgu_approved": True})
+        res = client.post(url, {"cgu_approved_at": now()})
         assertRedirects(res, settings.LOGIN_REDIRECT_URL)
 
 
diff --git a/core/views/forms.py b/core/views/forms.py
index 276995e6..c0510c7d 100644
--- a/core/views/forms.py
+++ b/core/views/forms.py
@@ -110,6 +110,12 @@ class FutureDateTimeField(forms.DateTimeField):
 
 
 class CGUApprovalField(forms.BooleanField):
+    """Form field with a checkbox to approve the CGUs.
+
+    The checkbox must be checked to be valid.
+    If valid, then the value of the field is the current timestamp.
+    """
+
     default_error_messages = {"required": _("You must approve the terms of service.")}
     __label = None
 
@@ -124,6 +130,9 @@ class CGUApprovalField(forms.BooleanField):
         kwargs["required"] = True
         super().__init__(label_suffix=label_suffix, **kwargs)
 
+    def to_python(self, value):
+        return now() if super().to_python(value) else None
+
     def get_label(self):
         if not self.__label:
             url = reverse("core:page", kwargs={"page_name": settings.SITH_CGU_PAGE})
@@ -175,15 +184,28 @@ class RegisteringForm(UserCreationForm):
 
     class Meta:
         model = User
-        fields = ("first_name", "last_name", "email", "cgu_approved")
-        field_classes = {"email": AntiSpamEmailField, "cgu_approved": CGUApprovalField}
+        fields = ("first_name", "last_name", "email", "cgu_approved_at")
+        field_classes = {
+            "email": AntiSpamEmailField,
+            "cgu_approved_at": CGUApprovalField,
+        }
 
 
 class CGUApprovalForm(forms.ModelForm):
     class Meta:
         model = User
-        fields = ["cgu_approved"]
-        field_classes = {"cgu_approved": CGUApprovalField}
+        fields = ["cgu_approved_at"]
+        field_classes = {"cgu_approved_at": CGUApprovalField}
+
+    def __init__(self, *args, instance: User | None = None, **kwargs):
+        if instance:
+            # If this form is displayed,
+            # then we want the user to explicitly check the button.
+            # So we pretend cgu were never approved (even if they were).
+            # If we didn't do that, the button would be initially checked,
+            # even if the approval was done before the last CGU version.
+            instance.cgu_approved_at = False
+        super().__init__(*args, instance=instance, **kwargs)
 
 
 class UserProfileForm(forms.ModelForm):
diff --git a/core/views/user.py b/core/views/user.py
index 4e16bf64..4fad761f 100644
--- a/core/views/user.py
+++ b/core/views/user.py
@@ -89,7 +89,7 @@ class SithLoginView(views.LoginView):
     def get_success_url(self) -> str:
         redirect_to = self.get_redirect_url()
         default_url = self.get_default_redirect_url()
-        if not self.request.user.cgu_approved:
+        if not self.request.user.approved_current_cgu:
             query = {"next": redirect_to} if redirect_to else {}
             return reverse("core:approve_cgu", query=query)
         return redirect_to or default_url
@@ -205,7 +205,7 @@ class CGUApprovalView(views.RedirectURLMixin, UpdateView):
     def dispatch(self, request, *args, **kwargs):
         if self.request.user.is_anonymous:
             return redirect("core:login")
-        if self.request.user.cgu_approved:
+        if self.request.user.approved_current_cgu:
             return redirect(self.get_success_url())
         return super().dispatch(request, *args, **kwargs)