diff --git a/openfisca_france/model/prelevements_obligatoires/prelevements_sociaux/cotisations_sociales/allegements.py b/openfisca_france/model/prelevements_obligatoires/prelevements_sociaux/cotisations_sociales/allegements.py
index ae19e34930..a57f9b5740 100644
--- a/openfisca_france/model/prelevements_obligatoires/prelevements_sociaux/cotisations_sociales/allegements.py
+++ b/openfisca_france/model/prelevements_obligatoires/prelevements_sociaux/cotisations_sociales/allegements.py
@@ -1,5 +1,6 @@
 import logging
 
+import numpy as np
 from numpy import busday_count, datetime64, logical_or as or_, logical_and as and_, timedelta64
 
 from openfisca_core.periods import Period