diff --git a/backend/src/routes/admin.ts b/backend/src/routes/admin.ts
index d6699eb..0246993 100644
--- a/backend/src/routes/admin.ts
+++ b/backend/src/routes/admin.ts
@@ -3,6 +3,9 @@ import { and, eq, inArray, isNull, sql } from "drizzle-orm";
 import multipart from "@fastify/multipart";
 import { DeleteObjectCommand, GetObjectCommand, PutObjectCommand } from "@aws-sdk/client-s3";
 import { randomUUID } from "node:crypto";
+import { createReadStream, createWriteStream } from "node:fs";
+import { stat, unlink } from "node:fs/promises";
+import { pipeline } from "node:stream/promises";
 
 import {
     authTenantUsers,
@@ -1446,6 +1449,7 @@ export default async function adminRoutes(server: FastifyInstance) {
     // -------------------------------------------------------------
     server.post("/admin/tenant-imports", { bodyLimit: 1024 * 1024 * 1024 }, async (req, reply) => {
         let archiveStoragePath: string | null = null;
+        let temporaryArchivePath: string | null = null;
         try {
             const currentUser = await requireAdmin(req, reply);
             if (!currentUser) return;
@@ -1469,13 +1473,19 @@ export default async function adminRoutes(server: FastifyInstance) {
                 }
 
                 archiveStoragePath = `tenant-imports/${randomUUID()}-${filename}`;
+                temporaryArchivePath = `${process.env.TMPDIR || "/tmp"}/fedeo-tenant-import-${randomUUID()}.zip`;
+                await pipeline(data.file, createWriteStream(temporaryArchivePath, { flags: "wx" }));
+                const temporaryArchive = await stat(temporaryArchivePath);
                 await s3.send(new PutObjectCommand({
                     Bucket: secrets.S3_BUCKET,
                     Key: archiveStoragePath,
-                    Body: data.file,
+                    Body: createReadStream(temporaryArchivePath),
+                    ContentLength: temporaryArchive.size,
                     ContentType: data.mimetype || "application/zip",
                 }));
-                fileSize = data.file.bytesRead || null;
+                fileSize = temporaryArchive.size;
+                await unlink(temporaryArchivePath);
+                temporaryArchivePath = null;
                 source = { archiveStoragePath };
             } else {
                 const body = req.body as TenantFullExport | { exportData?: TenantFullExport; targetTenantId?: number };
@@ -1520,6 +1530,11 @@ export default async function adminRoutes(server: FastifyInstance) {
             });
         } catch (err: any) {
             console.error("ERROR /admin/tenant-imports:", err);
+            if (temporaryArchivePath) {
+                await unlink(temporaryArchivePath).catch((cleanupError) => {
+                    console.error("ERROR cleanup temporary tenant import archive:", cleanupError);
+                });
+            }
             if (archiveStoragePath) {
                 await s3.send(new DeleteObjectCommand({
                     Bucket: secrets.S3_BUCKET,