diff --git a/manifests/init.pp b/manifests/init.pp
index ef4f809..2f33e39 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -213,7 +213,7 @@
 # Daniel Pawlik  <daniel.pawlik@corp.ovh.com>
 #
 class watcher (
-  $purge_config                         = false,
+  Boolean $purge_config                 = false,
   $use_ssl                              = false,
   $package_ensure                       = 'present',
   $rabbit_login_method                  = $facts['os_service_default'],
diff --git a/manifests/policy.pp b/manifests/policy.pp
index d566043..3e9c1a7 100644
--- a/manifests/policy.pp
+++ b/manifests/policy.pp
@@ -52,7 +52,7 @@ class watcher::policy (
   $policy_path          = '/etc/watcher/policy.yaml',
   $policy_default_rule  = $facts['os_service_default'],
   $policy_dirs          = $facts['os_service_default'],
-  $purge_config         = false,
+  Boolean $purge_config = false,
 ) {
 
   include watcher::deps