diff --git a/conftest.py b/conftest.py
index 423ebf97..c8d537fa 100644
--- a/conftest.py
+++ b/conftest.py
@@ -74,17 +74,27 @@ def serialize_callspec_between_getparam_and_setmulti(callspec):
 
     selected_attrs = attributes[start_index:end_index]
     data = {}
+
     for attr in selected_attrs:
         if attr != "indices":
             try:
                 value = getattr(callspec, attr)
                 if callable(value):
                     continue
-                data[attr] = safe_serialize(value)
+
+                # Forcer la sérialisation propre du champ 'params'
+                if attr == "params" and isinstance(value, dict):
+                    value = {str(k): safe_serialize(v) for k, v in value.items()}
+                else:
+                    value = safe_serialize(value)
+
+                data[attr] = value
             except Exception:
                 data[attr] = "<error>"
+
     return data
 
+
 runtime_params = []
 
 def pytest_runtest_makereport(item, call):