diff --git a/Sources/Modele/Echeance.cs b/Sources/Modele/Echeance.cs
index 5ad72a6..9925893 100644
--- a/Sources/Modele/Echeance.cs
+++ b/Sources/Modele/Echeance.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Text.Json.Serialization;
 using System.Threading.Tasks;
 
 namespace Model