diff --git a/api_signaling.go b/api_signaling.go
index 2edb10aa..84851f73 100644
--- a/api_signaling.go
+++ b/api_signaling.go
@@ -41,6 +41,9 @@ const (
 
 	// Version 2.0 validates auth params encoded as JWT.
 	HelloVersionV2 = "2.0"
+
+	ActorTypeUsers          = "users"
+	ActorTypeFederatedUsers = "federated_users"
 )
 
 var (
@@ -52,6 +55,17 @@ func makePtr[T any](v T) *T {
 	return &v
 }
 
+func getStringMapEntry[T any](m map[string]interface{}, key string) (s T, ok bool) {
+	var defaultValue T
+	v, found := m[key]
+	if !found {
+		return defaultValue, false
+	}
+
+	s, ok = v.(T)
+	return
+}
+
 // ClientMessage is a message that is sent from a client to the server.
 type ClientMessage struct {
 	json.Marshaler
diff --git a/federation.go b/federation.go
index ca012134..b93dacc3 100644
--- a/federation.go
+++ b/federation.go
@@ -55,6 +55,18 @@ func isClosedError(err error) bool {
 		strings.Contains(err.Error(), net.ErrClosed.Error())
 }
 
+func getCloudUrl(s string) string {
+	if strings.HasPrefix(s, "https://") {
+		s = s[8:]
+	} else {
+		s = strings.TrimPrefix(s, "http://")
+	}
+	if pos := strings.Index(s, "/ocs/v"); pos != -1 {
+		s = s[:pos]
+	}
+	return s
+}
+
 type FederationClient struct {
 	hub     *Hub
 	session *ClientSession
@@ -577,17 +589,36 @@ func (c *FederationClient) joinRoom() error {
 }
 
 func (c *FederationClient) updateEventUsers(users []map[string]interface{}, localSessionId string, remoteSessionId string) {
+	localCloudUrl := "@" + getCloudUrl(c.session.BackendUrl())
+	localCloudUrlLen := len(localCloudUrl)
+	remoteCloudUrl := "@" + getCloudUrl(c.federation.Load().NextcloudUrl)
+	checkSessionId := true
 	for _, u := range users {
-		key := "sessionId"
-		sid, found := u[key]
-		if !found {
-			key := "sessionid"
-			sid, found = u[key]
+		if actorType, found := getStringMapEntry[string](u, "actorType"); found {
+			if actorId, found := getStringMapEntry[string](u, "actorId"); found {
+				switch actorType {
+				case ActorTypeFederatedUsers:
+					if strings.HasSuffix(actorId, localCloudUrl) {
+						u["actorId"] = actorId[:len(actorId)-localCloudUrlLen]
+						u["actorType"] = ActorTypeUsers
+					}
+				case ActorTypeUsers:
+					u["actorId"] = actorId + remoteCloudUrl
+					u["actorType"] = ActorTypeFederatedUsers
+				}
+			}
 		}
-		if found {
-			if sid, ok := sid.(string); ok && sid == remoteSessionId {
+
+		if checkSessionId {
+			key := "sessionId"
+			sid, found := getStringMapEntry[string](u, key)
+			if !found {
+				key := "sessionid"
+				sid, found = getStringMapEntry[string](u, key)
+			}
+			if found && sid == remoteSessionId {
 				u[key] = localSessionId
-				break
+				checkSessionId = false
 			}
 		}
 	}
diff --git a/federation_test.go b/federation_test.go
index 0e31f155..a56edae2 100644
--- a/federation_test.go
+++ b/federation_test.go
@@ -24,6 +24,7 @@ package signaling
 import (
 	"context"
 	"encoding/json"
+	"strings"
 	"testing"
 	"time"
 
@@ -286,23 +287,53 @@ func Test_Federation(t *testing.T) {
 		}
 	}
 
-	// Simulate request from the backend that somebody joined the call.
+	// Simulate request from the backend that a federated user joined the call.
 	users := []map[string]interface{}{
 		{
 			"sessionId": remoteSessionId,
 			"inCall":    1,
+			"actorId":   "remoteUser@" + strings.TrimPrefix(server2.URL, "http://"),
+			"actorType": "federated_users",
 		},
 	}
 	room := hub1.getRoom(roomId)
 	require.NotNil(room)
 	room.PublishUsersInCallChanged(users, users)
 	var event *EventServerMessage
+	// For the local user, it's a federated user on server 2 that joined.
 	assert.NoError(checkReceiveClientEvent(ctx, client1, "update", &event))
 	assert.Equal(remoteSessionId, event.Update.Users[0]["sessionId"])
+	assert.Equal("remoteUser@"+strings.TrimPrefix(server2.URL, "http://"), event.Update.Users[0]["actorId"])
+	assert.Equal("federated_users", event.Update.Users[0]["actorType"])
 	assert.Equal(roomId, event.Update.RoomId)
-
+	// For the federated user, it's a local user that joined.
 	assert.NoError(checkReceiveClientEvent(ctx, client2, "update", &event))
 	assert.Equal(hello2.Hello.SessionId, event.Update.Users[0]["sessionId"])
+	assert.Equal("remoteUser", event.Update.Users[0]["actorId"])
+	assert.Equal("users", event.Update.Users[0]["actorType"])
+	assert.Equal(federatedRoomId, event.Update.RoomId)
+
+	// Simulate request from the backend that a local user joined the call.
+	users = []map[string]interface{}{
+		{
+			"sessionId": hello1.Hello.SessionId,
+			"inCall":    1,
+			"actorId":   "localUser",
+			"actorType": "users",
+		},
+	}
+	room.PublishUsersInCallChanged(users, users)
+	// For the local user, it's a local user that joined.
+	assert.NoError(checkReceiveClientEvent(ctx, client1, "update", &event))
+	assert.Equal(hello1.Hello.SessionId, event.Update.Users[0]["sessionId"])
+	assert.Equal("localUser", event.Update.Users[0]["actorId"])
+	assert.Equal("users", event.Update.Users[0]["actorType"])
+	assert.Equal(roomId, event.Update.RoomId)
+	// For the federated user, it's a federated user on server 1 that joined.
+	assert.NoError(checkReceiveClientEvent(ctx, client2, "update", &event))
+	assert.Equal(hello1.Hello.SessionId, event.Update.Users[0]["sessionId"])
+	assert.Equal("localUser@"+strings.TrimPrefix(server1.URL, "http://"), event.Update.Users[0]["actorId"])
+	assert.Equal("federated_users", event.Update.Users[0]["actorType"])
 	assert.Equal(federatedRoomId, event.Update.RoomId)
 
 	// Joining another "direct" session will trigger correct events.