diff --git a/src/core/Deal.Api/Endpoints/OperatorTenantsEndpoints.cs b/src/core/Deal.Api/Endpoints/OperatorTenantsEndpoints.cs
index bafc30c..73f8f05 100644
--- a/src/core/Deal.Api/Endpoints/OperatorTenantsEndpoints.cs
+++ b/src/core/Deal.Api/Endpoints/OperatorTenantsEndpoints.cs
@@ -144,12 +144,7 @@ public static class OperatorTenantsEndpoints
             return EndpointResults.Unauthorized(AuthHelpers.OperatorUnauthorizedDetail);
         }
 
-        TenantDetailDto? tenant = await tenantAdminService.GetAsync(id, ct);
-        if (tenant is null)
-        {
-            return EndpointResults.NotFound(TenantNotFoundDetail);
-        }
-
+        TenantDetailDto tenant = await tenantAdminService.GetAsync(id, ct);
         return Results.Ok(tenant);
     }
 
diff --git a/src/core/Deal.Modules.Tenants/Application/Services/TenantAdminService.cs b/src/core/Deal.Modules.Tenants/Application/Services/TenantAdminService.cs
index 7a4a553..70ec5f5 100644
--- a/src/core/Deal.Modules.Tenants/Application/Services/TenantAdminService.cs
+++ b/src/core/Deal.Modules.Tenants/Application/Services/TenantAdminService.cs
@@ -1,6 +1,7 @@
 using Deal.Modules.Tenants.Application.Abstractions;
 using Deal.Modules.Tenants.Application.Models;
 using Deal.SharedKernel;
+using Deal.SharedKernel.Errors;
 using Deal.SharedKernel.Utilities;
 
 namespace Deal.Modules.Tenants.Application.Services;
@@ -17,6 +18,9 @@ public sealed class TenantAdminService(
     // Случайные байты одноразового пароля владельца: 12 → ровно 16 символов Base64Url (как InviteCodeGenerator).
     private const int InitialPasswordRandomByteCount = 12;
 
+    // Имя сущности для текста ошибки «не найдено» (пользователь = тенант с его окружением).
+    private const string TenantEntityName = "Пользователь";
+
     /// <summary>
     /// Создаёт тенанта оператором
     /// </summary>
@@ -103,14 +107,12 @@ public sealed class TenantAdminService(
     /// Детали тенанта с пользователями
     /// </summary>
     /// <param name="id">Идентификатор тенанта.</param>
-    /// <returns>Детали и пользователи тенанта (по CreatedAt) или null, если тенанта нет.</returns>
-    public async Task<TenantDetailDto?> GetAsync(Guid id, CancellationToken ct)
+    /// <returns>Детали и пользователи тенанта (по CreatedAt).</returns>
+    /// <exception cref="NotFoundException">Тенант не найден.</exception>
+    public async Task<TenantDetailDto> GetAsync(Guid id, CancellationToken ct)
     {
-        var tenant = await tenantRepository.FindByIdAsync(id, ct);
-        if (tenant is null)
-        {
-            return null;
-        }
+        var tenant = await tenantRepository.FindByIdAsync(id, ct)
+            ?? throw new NotFoundException(TenantEntityName, id.ToString("N"));
 
         IReadOnlyList<UserIdentityDto> users = await authStore.ListUsersByTenantIdAsync(id, ct);
         return new TenantDetailDto(tenant.Id, tenant.Name, tenant.Status, tenant.CreatedAt, users);
diff --git a/src/core/tests/Deal.Tests.Unit/Modules/Tenants/TenantAdminServiceTests.cs b/src/core/tests/Deal.Tests.Unit/Modules/Tenants/TenantAdminServiceTests.cs
index e0cb343..111639f 100644
--- a/src/core/tests/Deal.Tests.Unit/Modules/Tenants/TenantAdminServiceTests.cs
+++ b/src/core/tests/Deal.Tests.Unit/Modules/Tenants/TenantAdminServiceTests.cs
@@ -1,7 +1,8 @@
+using Deal.Modules.Tenants.Application.Abstractions;
 using Deal.Modules.Tenants.Application.Models;
 using Deal.Modules.Tenants.Application.Services;
+using Deal.SharedKernel.Errors;
 using Deal.Tests.Unit.Support;
-using Deal.Modules.Tenants.Application.Abstractions;
 
 namespace Deal.Tests.Unit.Modules.Tenants;
 
@@ -148,11 +149,12 @@ public sealed class TenantAdminServiceTests
     }
 
     [Fact]
-    public async Task GetAsync_ForUnknownTenant_ReturnsNull()
+    public async Task GetAsync_ForUnknownTenant_ThrowsNotFound()
     {
         var service = NewService(new TestTenantStore(), new TestAuthStore());
 
-        Assert.Null(await service.GetAsync(Guid.NewGuid(), CancellationToken.None));
+        await Assert.ThrowsAsync<NotFoundException>(
+            () => service.GetAsync(Guid.NewGuid(), CancellationToken.None));
     }
 
     [Fact]