diff --git a/surveys.go b/surveys.go
index b77fa43..0c4e2cc 100644
--- a/surveys.go
+++ b/surveys.go
@@ -53,7 +53,12 @@ func init() {
 	}, adminRestricted))
 	router.GET("/api/surveys/:sid", apiAuthHandler(surveyAuthHandler(
 		func(s Survey, u *User, _ []byte) HTTPResponse {
-			if ((u != nil && s.Promo == u.Promo) && (s.Group == "" || (u != nil && strings.Contains(u.Groups, ","+s.Group+",")) && s.Shown)) || (u != nil && u.IsAdmin) {
+			if u == nil {
+				return APIErrorResponse{
+					status: http.StatusUnauthorized,
+					err:    errors.New("Veuillez vous connecter pour accéder à cette page."),
+				}
+			} else if (s.Promo == u.Promo && (s.Group == "" || strings.Contains(u.Groups, ","+s.Group+",") && s.Shown)) || u.IsAdmin {
 				return APIResponse{s}
 			} else {
 				return APIErrorResponse{