diff --git a/golem_activity_session/models/golem_activity_session.py b/golem_activity_session/models/golem_activity_session.py
index 011fbbb..c7e7936 100644
--- a/golem_activity_session/models/golem_activity_session.py
+++ b/golem_activity_session/models/golem_activity_session.py
@@ -61,6 +61,13 @@ class GolemActivitySession(models.Model):
             s.name = s.activity_id.activity_name
 
     member_ids = fields.Many2many('golem.member', string='Members')
+    places_used = fields.Integer('Places used', compute='_compute_places_used')
+
+    @api.depends('member_ids')
+    def _compute_places_used(self):
+        for s in self:
+            s.places_used = len(s.member_ids)
+
     # TODO: recurrence etc... to link with calendar.event
     activity_id = fields.Many2one('golem.activity', string='Activité',
                                   required=True)
@@ -86,6 +93,8 @@ class GolemActivitySession(models.Model):
                                                'after end of the period.'))
 
     places = fields.Integer('Places', default=0)
+    places_min = fields.Integer('Minimum places', default=0,
+                                help="Minimum places to maintain the session")
     is_overbooked = fields.Boolean('Allow overbook?', default=False)
     places_overbooked = fields.Integer('Places with overbook', default=0)
     places_remain = fields.Integer('Remaining places', store=True,
diff --git a/golem_activity_session/views/golem_activity_view.xml b/golem_activity_session/views/golem_activity_view.xml
index 0b28634..59d420d 100644
--- a/golem_activity_session/views/golem_activity_view.xml
+++ b/golem_activity_session/views/golem_activity_view.xml
@@ -44,6 +44,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
                 <field name="activity_id" />
                 <field name="animator_id" />
                 <field name="places" />
+                <field name="places_min" />
                 <field name="is_overbooked" />
                 <field name="places_overbooked"
                   attrs="{'invisible': [('is_overbooked', '=', False)]}" />
@@ -76,12 +77,18 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
       <field name="name">Session list</field>
       <field name="model">golem.activity.session</field>
       <field name="arch" type="xml">
-        <tree>
+        <tree colors="darkgrey: places_used &lt; places_min;
+          red: places_remain == 0;
+          orange: places_remain &lt;= 4;">
           <field name="activity_id" />
           <field name="animator_id" />
-          <field name="weekday" />
-          <field name="hour_start" />
-          <field name="hour_end" />
+          <field name="weekday" string="Day" />
+          <field name="hour_start" string="Start" />
+          <field name="hour_end" string="End" />
+          <field name="places" />
+          <field name="places_min" string="Min." />
+          <field name="places_remain" string="Remain" />
+          <field name="places_used" invisible="True" />
         </tree>
       </field>
     </record>