diff --git a/server/invoiceExtractor.test.ts b/server/invoiceExtractor.test.ts
new file mode 100644
index 0000000..e29a56f
--- /dev/null
+++ b/server/invoiceExtractor.test.ts
@@ -0,0 +1,29 @@
+import { describe, expect, it } from "vitest";
+import { cleanJsonResponse } from "./invoiceExtractor";
+
+describe("cleanJsonResponse", () => {
+  it("supprime les caractères de contrôle bruts dans une chaîne JSON LLM", () => {
+    const rawResponse = `{
+      "pageCount": 1,
+      "invoiceCount": 1,
+      "invoices": [{
+        "supplierName": "Manus AI",
+        "invoiceNumber": "J6LNGDAL-0021",
+        "extractedText": "Ligne valide\u0000suite du texte"
+      }]
+    }`;
+
+    const parsed = JSON.parse(cleanJsonResponse(rawResponse));
+
+    expect(parsed.invoices[0].invoiceNumber).toBe("J6LNGDAL-0021");
+    expect(parsed.invoices[0].extractedText).toBe("Ligne validesuite du texte");
+  });
+
+  it("préserve les retours à la ligne échappés dans les chaînes JSON", () => {
+    const rawResponse = '{"invoices":[{"extractedText":"Ligne 1\nLigne 2"}] }';
+
+    const parsed = JSON.parse(cleanJsonResponse(rawResponse));
+
+    expect(parsed.invoices[0].extractedText).toBe("Ligne 1\nLigne 2");
+  });
+});
diff --git a/server/invoiceExtractor.ts b/server/invoiceExtractor.ts
index e29b876..c129b43 100644
--- a/server/invoiceExtractor.ts
+++ b/server/invoiceExtractor.ts
@@ -75,9 +75,54 @@ async function extractTextFromPdf(pdfBuffer: Buffer): Promise<string> {
 }
 
 /**
- * Clean JSON response from LLM by removing markdown code blocks
+ * Supprime ou échappe les caractères de contrôle bruts uniquement à
+ * l'intérieur des chaînes JSON. Certains moteurs retournent ponctuellement
+ * un caractère NUL provenant du texte OCR : JSON.parse le refuse alors que
+ * le reste de la réponse est exploitable.
  */
-function cleanJsonResponse(content: string): string {
+function normalizeControlCharactersInJsonStrings(content: string): string {
+  let normalized = "";
+  let inString = false;
+  let escaped = false;
+
+  for (const character of content) {
+    if (escaped) {
+      normalized += character;
+      escaped = false;
+      continue;
+    }
+
+    if (character === "\\") {
+      normalized += character;
+      escaped = true;
+      continue;
+    }
+
+    if (character === '"') {
+      inString = !inString;
+      normalized += character;
+      continue;
+    }
+
+    if (inString && character.charCodeAt(0) < 0x20) {
+      if (character === "\n") normalized += "\\n";
+      else if (character === "\r") normalized += "\\r";
+      else if (character === "\t") normalized += "\\t";
+      // Les autres contrôles (notamment NUL) n'ont pas de valeur métier.
+      continue;
+    }
+
+    normalized += character;
+  }
+
+  return normalized;
+}
+
+/**
+ * Clean JSON response from LLM by removing markdown code blocks.
+ * Exportée pour couvrir les réponses LLM mal formées en régression.
+ */
+export function cleanJsonResponse(content: string): string {
   let cleaned = content.trim();
   
   // Remove markdown code blocks
@@ -123,7 +168,7 @@ function cleanJsonResponse(content: string): string {
     cleaned = cleaned.substring(startIdx, endIdx + 1);
   }
   
-  return cleaned;
+  return normalizeControlCharactersInJsonStrings(cleaned);
 }
 
 /**