diff --git a/server/db.ts b/server/db.ts
index 196c197..f6de05a 100644
--- a/server/db.ts
+++ b/server/db.ts
@@ -414,23 +414,25 @@ export async function getInvoiceStats(userId: number) {
 }
 
 export async function findDuplicateInvoice(
-  supplierName: string | null,
   invoiceNumber: string | null,
-  invoiceDate: Date | null
+  totalAmount: string | null,
+  userId?: number
 ): Promise<Invoice | undefined> {
-  if (!supplierName || !invoiceNumber || !invoiceDate) return undefined;
+  if (!invoiceNumber || !totalAmount) return undefined;
   
   const db = await getDb();
   if (!db) return undefined;
   
+  const conditions = [
+    eq(invoices.invoiceNumber, invoiceNumber),
+    eq(invoices.totalAmount, totalAmount),
+  ];
+  if (userId !== undefined) {
+    conditions.push(eq(invoices.userId, userId));
+  }
+  
   const result = await db.select().from(invoices)
-    .where(
-      and(
-        eq(invoices.supplierName, supplierName),
-        eq(invoices.invoiceNumber, invoiceNumber),
-        eq(invoices.invoiceDate, invoiceDate)
-      )
-    )
+    .where(and(...conditions))
     .limit(1);
   
   return result[0];
diff --git a/server/emailImportService.ts b/server/emailImportService.ts
index fe6d0b3..fbcea72 100644
--- a/server/emailImportService.ts
+++ b/server/emailImportService.ts
@@ -129,11 +129,11 @@ async function processEmailAttachment(
           processingProgress: `Extraction ${i + 1}/${result.invoiceCount} factures...`,
         });
         
-        // Check for duplicates
+        // Check for duplicates (numéro de facture + montant)
         const duplicate = await findDuplicateInvoice(
-          invoiceData.supplierName,
           invoiceData.invoiceNumber,
-          invoiceData.invoiceDate
+          invoiceData.totalAmount?.toString() ?? null,
+          userId
         );
         
         if (duplicate) {
@@ -141,7 +141,7 @@ async function processEmailAttachment(
           duplicateDetails.push({
             supplierName: invoiceData.supplierName,
             invoiceNumber: invoiceData.invoiceNumber,
-            invoiceDate: invoiceData.invoiceDate,
+            totalAmount: invoiceData.totalAmount,
           });
           continue;
         }
diff --git a/server/folderImportService.ts b/server/folderImportService.ts
index 66b6998..6989d73 100644
--- a/server/folderImportService.ts
+++ b/server/folderImportService.ts
@@ -115,11 +115,11 @@ async function processFolderFile(
           processingProgress: `Extraction ${i + 1}/${result.invoiceCount} factures...`,
         });
         
-        // Check for duplicates
+        // Check for duplicates (numéro de facture + montant)
         const duplicate = await findDuplicateInvoice(
-          invoiceData.supplierName,
           invoiceData.invoiceNumber,
-          invoiceData.invoiceDate
+          invoiceData.totalAmount?.toString() ?? null,
+          userId
         );
         
         if (duplicate) {
@@ -127,7 +127,7 @@ async function processFolderFile(
           duplicateDetails.push({
             supplierName: invoiceData.supplierName,
             invoiceNumber: invoiceData.invoiceNumber,
-            invoiceDate: invoiceData.invoiceDate,
+            totalAmount: invoiceData.totalAmount,
           });
           continue;
         }
diff --git a/server/routers.ts b/server/routers.ts
index d29b457..cf59dbe 100644
--- a/server/routers.ts
+++ b/server/routers.ts
@@ -252,11 +252,11 @@ export const appRouter = router({
                   processingProgress: `Extraction ${i + 1}/${result.invoiceCount} factures...`,
                 });
                 
-                // Check for duplicates
+                // Check for duplicates (numéro de facture + montant)
                 const duplicate = await findDuplicateInvoice(
-                  invoiceData.supplierName,
                   invoiceData.invoiceNumber,
-                  invoiceData.invoiceDate
+                  invoiceData.totalAmount?.toString() ?? null,
+                  userId
                 );
                 
                 if (duplicate) {
@@ -264,7 +264,7 @@ export const appRouter = router({
                   duplicateDetails.push({
                     supplierName: invoiceData.supplierName,
                     invoiceNumber: invoiceData.invoiceNumber,
-                    invoiceDate: invoiceData.invoiceDate,
+                    totalAmount: invoiceData.totalAmount,
                   });
                   continue;
                 }