diff --git a/toucan_connectors/mongo/mongo_connector.py b/toucan_connectors/mongo/mongo_connector.py
index 9f6d955bd..c56529e93 100644
--- a/toucan_connectors/mongo/mongo_connector.py
+++ b/toucan_connectors/mongo/mongo_connector.py
@@ -5,7 +5,7 @@
 import pymongo
 from bson.son import SON
 from cached_property import cached_property
-from pydantic import ConfigDict, Field, create_model, model_validator
+from pydantic import ConfigDict, Field, create_model, field_validator, model_validator
 
 from toucan_connectors.common import ConnectorStatus, nosql_apply_parameters_to_query
 from toucan_connectors.json_wrapper import JsonWrapper
@@ -116,8 +116,15 @@ class MongoDataSource(ToucanDataSource):
         'Aggregation Pipeline in the MongoDB documentation',
     )
 
+    # FIXME: This is needed for now because with we rely on empty queries being dicts. In pydantic
+    # v1, "[]" was coerced to {}
+    @field_validator("query")
     @classmethod
-    def get_form(cls, connector: 'MongoConnector', current_config):
+    def _ensure_empty_query_is_dict(cls, query: dict | list) -> dict | list:
+        return query or {}
+
+    @classmethod
+    def get_form(cls, connector: "MongoConnector", current_config):
         """
         Method to retrieve the form with a current config
         For example, once the connector is set,