diff --git a/backend/src/routes/communication.ts b/backend/src/routes/communication.ts
index 7412e94..e61fd86 100644
--- a/backend/src/routes/communication.ts
+++ b/backend/src/routes/communication.ts
@@ -1,7 +1,7 @@
 import { createHash } from "node:crypto"
 import { FastifyInstance } from "fastify"
 import multipart from "@fastify/multipart"
-import { and, eq, inArray, ne } from "drizzle-orm"
+import { and, desc, eq, inArray, ne } from "drizzle-orm"
 import { authProfiles, authTenantUsers, authUsers, notificationsItems, projects } from "../../db/schema"
 import { matrixService } from "../modules/matrix.service"
 import { NotificationService, UserDirectory } from "../modules/notification.service"
@@ -98,6 +98,30 @@ export default async function communicationRoutes(server: FastifyInstance) {
             ))
     }
 
+    const getTenantUser = async (tenantId: number, userId: string): Promise<ChatRecipient | null> => {
+        const [user] = await server.db
+            .select({
+                userId: authTenantUsers.user_id,
+                email: authUsers.email,
+                firstName: authProfiles.first_name,
+                lastName: authProfiles.last_name,
+                fullName: authProfiles.full_name,
+            })
+            .from(authTenantUsers)
+            .innerJoin(authUsers, eq(authUsers.id, authTenantUsers.user_id))
+            .leftJoin(authProfiles, and(
+                eq(authProfiles.user_id, authTenantUsers.user_id),
+                eq(authProfiles.tenant_id, tenantId)
+            ))
+            .where(and(
+                eq(authTenantUsers.tenant_id, tenantId),
+                eq(authTenantUsers.user_id, userId)
+            ))
+            .limit(1)
+
+        return user || null
+    }
+
     const getSenderName = async (tenantId: number, senderUserId: string) => {
         const [sender] = await server.db
             .select({
@@ -195,6 +219,67 @@ export default async function communicationRoutes(server: FastifyInstance) {
         }
     }
 
+    const hasChatNotificationForMessage = async (tenantId: number, userId: string, messageId: string) => {
+        const rows = await server.db
+            .select({
+                payload: notificationsItems.payload,
+            })
+            .from(notificationsItems)
+            .where(and(
+                eq(notificationsItems.tenantId, tenantId),
+                eq(notificationsItems.userId, userId),
+                eq(notificationsItems.eventType, "communication.message.new")
+            ))
+            .orderBy(desc(notificationsItems.createdAt))
+            .limit(200)
+
+        return rows.some((row) => (row.payload as any)?.messageId === messageId)
+    }
+
+    const notifyCurrentUserAboutIncomingMatrixMessages = async (req: any, room: any, messages: any[]) => {
+        if (!req.user.tenant_id || !messages.length) return
+
+        try {
+            const currentUser = await getTenantUser(req.user.tenant_id, req.user.user_id)
+            if (!currentUser) return
+
+            for (const message of messages) {
+                if (message.own || !message.id) continue
+
+                const text = message.body || message.attachment?.fileName || "Neue Nachricht"
+                const mentioned = mentionedRecipientIds(text, [currentUser]).includes(currentUser.userId)
+                const direct = room?.type === "direct"
+
+                if (!direct && !mentioned) continue
+                if (await hasChatNotificationForMessage(req.user.tenant_id, req.user.user_id, message.id)) continue
+
+                const senderName = message.senderDisplayName || message.sender || "Matrix"
+                const preview = text.length > 160 ? `${text.slice(0, 157)}...` : text
+
+                await notifications.trigger({
+                    tenantId: req.user.tenant_id,
+                    userId: req.user.user_id,
+                    eventType: "communication.message.new",
+                    title: mentioned ? `${senderName} hat dich erwähnt` : `Neue Direktnachricht von ${senderName}`,
+                    message: preview,
+                    payload: {
+                        link: `/communication/chat?room=${encodeURIComponent(room.key)}`,
+                        roomKey: room.key,
+                        roomName: room.name,
+                        roomType: room.type,
+                        messageId: message.id,
+                        matrixSender: message.sender,
+                        mentioned,
+                        direct,
+                    },
+                    channels: ["inapp", "push"],
+                })
+            }
+        } catch (err) {
+            req.log.error({ err }, "Eingehende Matrix-Benachrichtigung konnte nicht ausgelöst werden")
+        }
+    }
+
     const unreadChatNotifications = async (tenantId: number, userId: string) => {
         return await server.db
             .select({
@@ -739,13 +824,19 @@ export default async function communicationRoutes(server: FastifyInstance) {
     server.get("/communication/matrix/rooms/:roomKey/sync", async (req, reply) => {
         try {
             const query = req.query as { since?: string; initial?: string }
-            return await matrix.syncTenantRoomEvents(
+            const result = await matrix.syncTenantRoomEvents(
                 req.user.user_id,
                 req.user.tenant_id,
                 roomOptionsFromRequest(req),
                 query.since,
                 query.initial === "1"
             )
+            if (query.since && query.initial !== "1" && result.messages?.length) {
+                const room = await matrix.getTenantRoomStatus(req.user.tenant_id, result.key, result.name)
+                await notifyCurrentUserAboutIncomingMatrixMessages(req, room, result.messages)
+            }
+
+            return result
         } catch (err: any) {
             return handleMatrixError(req, reply, err, "Matrix sync failed")
         }