diff --git a/ontology/saref4wear.ttl b/ontology/saref4wear.ttl
index 53afce16229ae117c463abc28936f2f9c41d2f4b..33f96b395b26e755b392b17a764744278c911b32 100644
--- a/ontology/saref4wear.ttl
+++ b/ontology/saref4wear.ttl
@@ -111,6 +111,13 @@ geo:location rdf:type owl:ObjectProperty ;
                    rdfs:label "location" .
 
 
+## https://saref.etsi.org/saref4city#takesPlaceAtFacility
+
+s4city:takesPlaceAtFacility rdf:type owl:ObjectProperty ;
+                            rdfs:isDefinedBy <https://saref.etsi.org/saref4city#> ;
+	                        rdfs:label "takes place at facility"@en .
+
+
 ###  https://saref.etsi.org/s4wear#canSendInformationTo
 s4wear:canSendInformationTo rdf:type owl:ObjectProperty ;
                             rdfs:domain s4wear:Wearable ;
@@ -242,7 +249,7 @@ s4wear:hasCapacity rdf:type owl:DatatypeProperty ;
 
 ###  https://saref.etsi.org/s4wear#eventType
 s4wear:eventType rdf:type owl:DatatypeProperty ;
-                 rdfs:domain s4wear:Event ;
+                 rdfs:domain s4city:Event ;
                  rdfs:range xsd:string .
 
 
@@ -346,6 +353,16 @@ s4city:CityObject rdf:type owl:Class ;
                   rdfs:label "City object"@en .
 
 
+## https://saref.etsi.org/saref4city#Event
+s4city:Event rdf:type owl:Class ;
+             rdfs:subClassOf [	a owl:Restriction ; 
+				         		owl:onProperty s4city:takesPlaceAtFacility ;
+					        	owl:allValuesFrom s4city:Facility 
+					         ] ;
+             rdfs:isDefinedBy <https://saref.etsi.org/saref4city#> ;
+             rdfs:label "Event"@en .
+
+
 ## https://saref.etsi.org/saref4city#Facility
 s4city:Facility rdf:type owl:Class ;
 	            rdfs:subClassOf geosp:Feature ;
@@ -391,10 +408,6 @@ s4wear:Emission rdf:type owl:Class ;
 s4wear:Entity rdf:type owl:Class .
 
 
-###  https://saref.etsi.org/s4wear#Event
-s4wear:Event rdf:type owl:Class .
-
-
 ###  https://saref.etsi.org/s4wear#Fabric
 s4wear:Fabric rdf:type owl:Class ;
               rdfs:subClassOf s4wear:TextileBasedWearable .