diff --git a/weboob/backends/sfr/backend.py b/weboob/backends/sfr/backend.py
index 72ec8c36..fd7fdb90 100644
--- a/weboob/backends/sfr/backend.py
+++ b/weboob/backends/sfr/backend.py
@@ -18,7 +18,7 @@
 
 from __future__ import with_statement
 
-from weboob.capabilities.messages import ICapMessagesPost
+from weboob.capabilities.messages import CantSendMessage, ICapMessagesPost
 from weboob.tools.backend import BaseBackend
 from weboob.tools.value import ValuesDict, Value
 
@@ -45,4 +45,6 @@ class SfrBackend(BaseBackend, ICapMessagesPost):
     # ICapMessagesPost methods
 
     def post_message(self, message):
+        if not message.content.strip():
+            raise CantSendMessage(u'Message content is empty.')
         self.browser.post_message(message)
diff --git a/weboob/backends/sfr/browser.py b/weboob/backends/sfr/browser.py
index c8220353..e4b2099f 100644
--- a/weboob/backends/sfr/browser.py
+++ b/weboob/backends/sfr/browser.py
@@ -21,7 +21,6 @@ import urllib
 from .pages.compose import ClosePage, ComposePage, ConfirmPage, SentPage
 from .pages.login import LoginPage
 
-from weboob.capabilities.messages import CantSendMessage
 from weboob.tools.browser import BaseBrowser, BrowserIncorrectPassword
 
 
@@ -57,5 +56,4 @@ class SfrBrowser(BaseBrowser):
         self.page.post_message(message)
         if self.is_on_page(ConfirmPage):
             self.page.confirm()
-        if self.is_on_page(ClosePage):
-            raise CantSendMessage('Invalid receiver.')
+        assert self.is_on_page(ClosePage) or self.is_on_page(SentPage)
diff --git a/weboob/backends/sfr/pages/compose.py b/weboob/backends/sfr/pages/compose.py
index 2791dc99..ca00e4ea 100644
--- a/weboob/backends/sfr/pages/compose.py
+++ b/weboob/backends/sfr/pages/compose.py
@@ -16,6 +16,9 @@
 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 
+import re
+
+from weboob.capabilities.messages import CantSendMessage
 from weboob.tools.browser import BasePage
 
 
@@ -27,7 +30,13 @@ class ClosePage(BasePage):
 
 
 class ComposePage(BasePage):
+    phone_regex = re.compile('^(\+33|0033|0)(6|7)(\d{8})$')
+
     def post_message(self, message):
+        receiver_list = [receiver.strip() for receiver in message.receiver.split(',')]
+        for receiver in receiver_list:
+            if self.phone_regex.match(receiver) is None:
+                raise CantSendMessage(u'Invalid receiver: %s' % receiver)
         self.browser.select_form(nr=0)
         self.browser['msisdns'] = message.receiver
         self.browser['textMessage'] = message.content