diff --git a/src/bot.ts b/src/bot.ts
index 4230b6b..8ee489f 100644
--- a/src/bot.ts
+++ b/src/bot.ts
@@ -6,7 +6,7 @@ import { createLogger } from './utils/logger.js';
 const log = createLogger('Bot');
 
 interface SessionData {
-  selectedTenantId: number;
+  selectedTenantId: number | null;
   selectedTenantName: string;
 }
 
@@ -41,7 +41,7 @@ function createBot(): Bot<BotContext> {
     session({
       initial: (): SessionData => ({
         selectedTenantId: config.defaultTenantId,
-        selectedTenantName: 'Default',
+        selectedTenantName: config.defaultTenantId ? 'Default' : '',
       }),
     }),
   );
diff --git a/src/config.ts b/src/config.ts
index 780052f..bc9a1b7 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -10,7 +10,7 @@ interface Config {
     email: string;
     password: string;
   };
-  defaultTenantId: number;
+  defaultTenantId: number | null;
   logLevel: string;
   nodeEnv: string;
 }
@@ -43,7 +43,7 @@ export const config: Config = {
     email: requireEnv('PAYLOAD_ADMIN_EMAIL'),
     password: requireEnv('PAYLOAD_ADMIN_PASSWORD'),
   },
-  defaultTenantId: Number(process.env.DEFAULT_TENANT_ID || '4'),
+  defaultTenantId: process.env.DEFAULT_TENANT_ID ? Number(process.env.DEFAULT_TENANT_ID) : null,
   logLevel: process.env.LOG_LEVEL || 'info',
   nodeEnv: process.env.NODE_ENV || 'development',
 };
diff --git a/src/telegram/handlers.ts b/src/telegram/handlers.ts
index 58aaae8..ffb1301 100644
--- a/src/telegram/handlers.ts
+++ b/src/telegram/handlers.ts
@@ -72,6 +72,10 @@ async function downloadTelegramFile(
   return { buffer, mimeType, filePath };
 }
 
+function requireTenant(ctx: BotContext): ctx is BotContext & { session: { selectedTenantId: number } } {
+  return ctx.session.selectedTenantId !== null;
+}
+
 async function processUpload(
   ctx: BotContext,
   fileId: string,
@@ -81,6 +85,15 @@ async function processUpload(
   const userId = ctx.from?.id;
   if (!userId) return;
 
+  if (!requireTenant(ctx)) {
+    await ctx.api.editMessageText(
+      ctx.chat!.id,
+      statusMessageId,
+      '⚠️ Bitte wähle zuerst einen Tenant mit /tenant',
+    );
+    return;
+  }
+
   // Rate limit check
   const rateCheck = checkRateLimit(userId);
   if (!rateCheck.allowed) {
@@ -129,6 +142,11 @@ async function processAlbum(
   ctx: BotContext,
   messages: Array<{ fileId: string; filename: string; mimeType: string }>,
 ): Promise<void> {
+  if (!requireTenant(ctx)) {
+    await ctx.reply('⚠️ Bitte wähle zuerst einen Tenant mit /tenant');
+    return;
+  }
+
   const total = Math.min(messages.length, 10);
   const statusMsg = await ctx.reply(`\u23f3 Album wird hochgeladen (0/${total})...`);
   let successCount = 0;
@@ -187,12 +205,18 @@ async function processAlbum(
 export function registerHandlers(bot: Bot<BotContext>): void {
   // /start command
   bot.command('start', async (ctx) => {
-    const tenantName = await getTenantName(ctx.session.selectedTenantId);
-    ctx.session.selectedTenantName = tenantName;
+    let tenantLine: string;
+    if (ctx.session.selectedTenantId !== null) {
+      const tenantName = await getTenantName(ctx.session.selectedTenantId);
+      ctx.session.selectedTenantName = tenantName;
+      tenantLine = `Aktueller Tenant: *${escapeMarkdown(tenantName)}*`;
+    } else {
+      tenantLine = `⚠️ *Kein Tenant gewählt* \\- nutze /tenant`;
+    }
 
     const text =
       `\ud83d\udcf7 *Payload Media Bot*\n\n` +
-      `Willkommen\\! Aktueller Tenant: *${escapeMarkdown(tenantName)}*\n\n` +
+      `Willkommen\\! ${tenantLine}\n\n` +
       `*Befehle:*\n` +
       `/tenant \\- Tenant wechseln\n` +
       `/list \\- Letzte 5 Medien anzeigen\n` +
@@ -216,6 +240,11 @@ export function registerHandlers(bot: Bot<BotContext>): void {
 
   // /list command — show last 5 media items
   bot.command('list', async (ctx) => {
+    if (!requireTenant(ctx)) {
+      await ctx.reply('⚠️ Bitte wähle zuerst einen Tenant mit /tenant');
+      return;
+    }
+
     try {
       const result = await payloadClient.listMedia(ctx.session.selectedTenantId, 5);
 
@@ -254,7 +283,7 @@ export function registerHandlers(bot: Bot<BotContext>): void {
       `\ud83d\udcca *Bot Status*\n\n` +
       `\u23f1 Uptime: ${escapeMarkdown(formatUptime())}\n` +
       `\ud83d\udfe2 API: ${healthy ? 'Erreichbar' : 'Nicht erreichbar'}\n` +
-      `\ud83c\udfe2 Tenant: ${escapeMarkdown(ctx.session.selectedTenantName)} \\(ID ${ctx.session.selectedTenantId}\\)\n` +
+      `\ud83c\udfe2 Tenant: ${ctx.session.selectedTenantId !== null ? `${escapeMarkdown(ctx.session.selectedTenantName)} \\(ID ${ctx.session.selectedTenantId}\\)` : 'Nicht gewählt'}\n` +
       `\ud83d\udd11 Token läuft ab: ${escapeMarkdown(expiryStr)}`;
 
     await ctx.reply(text, { parse_mode: 'MarkdownV2' });