diff --git a/opencti-platform/opencti-front/src/private/components/data/ToolBar.jsx b/opencti-platform/opencti-front/src/private/components/data/ToolBar.jsx
index 1e1f95b75395..38d4fad7fc77 100644
--- a/opencti-platform/opencti-front/src/private/components/data/ToolBar.jsx
+++ b/opencti-platform/opencti-front/src/private/components/data/ToolBar.jsx
@@ -1337,7 +1337,7 @@ class ToolBar extends Component {
             const currentMap = schema.filterKeysSchema.get(entityType);
             currentMap?.forEach((value, key) => filterKeysMap.set(key, value));
           });
-          const availableFilterKeys = Array.from(filterKeysMap.keys() ?? []).concat(['entity_type']);
+          const availableFilterKeys = Array.from(filterKeysMap.keys()).concat(['entity_type']);
           // endregion
           return (
             <Drawer
diff --git a/opencti-platform/opencti-graphql/src/domain/filterKeysSchema.ts b/opencti-platform/opencti-graphql/src/domain/filterKeysSchema.ts
index 04b5c8002881..228d19cacc38 100644
--- a/opencti-platform/opencti-graphql/src/domain/filterKeysSchema.ts
+++ b/opencti-platform/opencti-graphql/src/domain/filterKeysSchema.ts
@@ -3,9 +3,9 @@ import { schemaAttributesDefinition } from '../schema/schema-attributes';
 import { schemaTypesDefinition } from '../schema/schema-types';
 import type {
   AttributeDefinition,
+  ComplexAttributeWithMappings,
   EnumAttribute,
   IdAttribute,
-  NestedObjectAttribute,
   NumericAttribute,
   RefAttribute,
   StringAttribute,
@@ -138,23 +138,28 @@ const completeFilterDefinitionMapWithElement = (
   }
 };
 
-const completeFilterDefinitionMapWithNestedAttribute = (
+const completeFilterDefinitionMapWithObjectAttributeWithMappings = (
   attributesMapWithFilterDefinition: Map<string, FilterDefinition>, // map in construction
-  nestedAttributeDefinition: NestedObjectAttribute, // nested attribute to study
+  objectAttributeDefinition: ComplexAttributeWithMappings, // object attribute with mappings
   types: string[], // entity types to apply
 ) => {
-  const { mappings } = nestedAttributeDefinition;
+  const { mappings } = objectAttributeDefinition;
   mappings.forEach((mappingAttributeDefinition) => {
     if (mappingAttributeDefinition.isFilterable) {
-      if (mappingAttributeDefinition.type === 'object' && ['nested', 'standard'].includes(mappingAttributeDefinition.format)) { // case 1: nested attribute
-        throw Error('A nested attribute can\'t contain a nested attribute'); // not supported for the moment
-      } else if (mappingAttributeDefinition.associatedFilterKeys) { // case 2: not nested attribute and associatedFilterKeys is set
+      if (mappingAttributeDefinition.type === 'object' && ['nested', 'standard'].includes(mappingAttributeDefinition.format)) { // case 1: object attribute with mappings
+        const composedMappingName = `${objectAttributeDefinition.name}.${mappingAttributeDefinition.name}`;
+        completeFilterDefinitionMapWithObjectAttributeWithMappings(
+          attributesMapWithFilterDefinition,
+          { ...mappingAttributeDefinition, name: composedMappingName } as ComplexAttributeWithMappings,
+          types
+        );
+      } else if (mappingAttributeDefinition.associatedFilterKeys) { // case 2: attribute with no mappings and associatedFilterKeys is set
         // the keys to add are the ones in associatedFilterKeys
         mappingAttributeDefinition.associatedFilterKeys.forEach(({ key, label }) => {
           completeFilterDefinitionMapWithElement(attributesMapWithFilterDefinition, types, key, { ...mappingAttributeDefinition, name: key, label }, 'attribute');
         });
-      } else { // case 3: not nested attribute and the key to add is composed with the attribute name and the mapping attribute name
-        const composedMappingName = `${nestedAttributeDefinition.name}.${mappingAttributeDefinition.name}`;
+      } else { // case 3: attribute with no mappings and the key to add is composed with the attribute name and the mapping attribute name
+        const composedMappingName = `${objectAttributeDefinition.name}.${mappingAttributeDefinition.name}`;
         completeFilterDefinitionMapWithElement(attributesMapWithFilterDefinition, types, composedMappingName, { ...mappingAttributeDefinition, name: composedMappingName }, 'attribute');
       }
     }
@@ -172,8 +177,8 @@ const completeFilterDefinitionMapForType = (
   attributesMap.forEach((attributeDefinition, attributeName) => {
     if (attributeDefinition.isFilterable) { // if it is filterable
       if (attributeDefinition.type === 'object' && ['nested', 'standard'].includes(attributeDefinition.format)) { // case 1.1: attribute with mappings
-        completeFilterDefinitionMapWithNestedAttribute(filterDefinitionMap, attributeDefinition as NestedObjectAttribute, types);
-      } else { // case 1.2: not nested attribute
+        completeFilterDefinitionMapWithObjectAttributeWithMappings(filterDefinitionMap, attributeDefinition as ComplexAttributeWithMappings, types);
+      } else { // case 1.2: attribute with no mappings
         completeFilterDefinitionMapWithElement(filterDefinitionMap, types, attributeName, attributeDefinition, 'attribute');
       }
     }
diff --git a/opencti-platform/opencti-graphql/src/modules/notification/notification.ts b/opencti-platform/opencti-graphql/src/modules/notification/notification.ts
index da4bec2cecf1..5f8db7f1dc16 100644
--- a/opencti-platform/opencti-graphql/src/modules/notification/notification.ts
+++ b/opencti-platform/opencti-graphql/src/modules/notification/notification.ts
@@ -8,7 +8,7 @@ import {
   type StoreEntityNotification,
   type StoreEntityTrigger
 } from './notification-types';
-import { ABSTRACT_INTERNAL_OBJECT } from '../../schema/general';
+import { ABSTRACT_INTERNAL_OBJECT, ABSTRACT_STIX_CORE_OBJECT } from '../../schema/general';
 import type { ModuleDefinition } from '../../schema/module';
 import { registerDefinition } from '../../schema/module';
 import { authorizedAuthorities, authorizedMembers } from '../../schema/attribute-definition';
@@ -81,9 +81,9 @@ const NOTIFICATION_DEFINITION: ModuleDefinition<StoreEntityNotification, StixNot
       editDefault: false,
       multiple: true,
       upsert: false,
-      isFilterable: false,
+      isFilterable: true,
       mappings: [
-        { name: 'title', label: 'Notification title', type: 'string', format: 'short', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
+        { name: 'title', label: 'Notification title', type: 'string', format: 'short', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: false },
         {
           name: 'events',
           label: 'Notification events',
@@ -95,9 +95,9 @@ const NOTIFICATION_DEFINITION: ModuleDefinition<StoreEntityNotification, StixNot
           upsert: false,
           isFilterable: true,
           mappings: [
-            { name: 'message', label: 'Notification event message', type: 'string', format: 'text', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
-            { name: 'instance_id', label: 'Notification related instance', type: 'string', format: 'short', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
-            { name: 'operation', label: 'Notification operation', type: 'string', format: 'short', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
+            { name: 'message', label: 'Notification message', type: 'string', format: 'text', mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
+            { name: 'instance_id', label: 'Notification related instance', type: 'string', format: 'id', entityTypes: [ABSTRACT_STIX_CORE_OBJECT], mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: false },
+            { name: 'operation', label: 'Notification operation', type: 'string', format: 'enum', values: ['create', 'update', 'delete'], mandatoryType: 'internal', editDefault: false, multiple: false, upsert: false, isFilterable: true },
           ]
         },
       ]
diff --git a/opencti-platform/opencti-graphql/src/schema/attribute-definition.ts b/opencti-platform/opencti-graphql/src/schema/attribute-definition.ts
index 9486cc403435..7bfbc72e7e25 100644
--- a/opencti-platform/opencti-graphql/src/schema/attribute-definition.ts
+++ b/opencti-platform/opencti-graphql/src/schema/attribute-definition.ts
@@ -58,6 +58,7 @@ export type NestedObjectAttribute = { type: 'object', format: 'nested' } & Basic
 export type RefAttribute = { type: 'ref', databaseName: string, stixName: string, isRefExistingForTypes: Checker, datable?: boolean, toTypes: string[] } & BasicDefinition;
 export type StringAttribute = IdAttribute | TextAttribute | EnumAttribute | VocabAttribute | JsonAttribute;
 export type ComplexAttribute = FlatObjectAttribute | ObjectAttribute | NestedObjectAttribute;
+export type ComplexAttributeWithMappings = ObjectAttribute | NestedObjectAttribute;
 
 export type AttributeDefinition = NumericAttribute | DateAttribute | BooleanAttribute | StringAttribute | ComplexAttribute | RefAttribute;
 
diff --git a/opencti-platform/opencti-graphql/tests/01-unit/domain/filterKeysSchema-test.ts b/opencti-platform/opencti-graphql/tests/01-unit/domain/filterKeysSchema-test.ts
index 4cbd8196364e..9a7ab06104a2 100644
--- a/opencti-platform/opencti-graphql/tests/01-unit/domain/filterKeysSchema-test.ts
+++ b/opencti-platform/opencti-graphql/tests/01-unit/domain/filterKeysSchema-test.ts
@@ -120,6 +120,11 @@ describe('Filter keys schema generation testing', async () => {
     // 'LZJD hash' for observables (not filterable)
     filterDefinition = filterKeysSchema.get(ABSTRACT_STIX_CYBER_OBSERVABLE)?.get('hashes.LZJD');
     expect(filterDefinition).toBeUndefined(); // LZJD hash is not filterable
+    // 'operation' for notifications (mapping attribute in a mapping attribute)
+    filterDefinition = filterKeysSchema.get(ABSTRACT_STIX_CYBER_OBSERVABLE)?.get('notification_content.events.operation');
+    expect(filterDefinition?.filterKey).toEqual('notification_content.events.operation');
+    expect(filterDefinition?.type).toEqual('enum');
+    expect(filterDefinition?.elementsForFilterValuesSearch.length).toEqual(3); // create, update, delete
   });
   it('should construct correct filter definition for nested object attributes', () => {
     // 'fromId' for relationships