diff --git a/weboob/applications/boobsize/boobsize.py b/weboob/applications/boobsize/boobsize.py
index 9d0875ba..d81fa27e 100644
--- a/weboob/applications/boobsize/boobsize.py
+++ b/weboob/applications/boobsize/boobsize.py
@@ -55,10 +55,13 @@ class GaugeFormatter(IFormatter):
             for sensor in obj.sensors:
                 sensorname = sensor.name
                 # This is a int value, do not display it as a float
-                if int(sensor.lastvalue.level) == sensor.lastvalue.level:
-                    lastvalue = "%d " % sensor.lastvalue.level
+                if sensor.lastvalue.level:
+                    if int(sensor.lastvalue.level) == sensor.lastvalue.level:
+                        lastvalue = "%d " % sensor.lastvalue.level
+                    else:
+                        lastvalue = "%r " % sensor.lastvalue.level
                 else:
-                    lastvalue = "%r " % sensor.lastvalue.level
+                    lastvalue = u"? "
                 if not empty(sensor.unit):
                     lastvalue += "%s" % sensor.unit
                 if first: