diff --git a/src/fr/siret.spec.ts b/src/fr/siret.spec.ts
index a8f90bb..3bf249e 100644
--- a/src/fr/siret.spec.ts
+++ b/src/fr/siret.spec.ts
@@ -8,11 +8,21 @@ describe('fr/siret', () => {
     expect(result).toEqual('732 829 320 00074');
   });
 
-  it('validate:73282932000074', () => {
-    const result = validate('73282932000074');
-
-    expect(result.isValid && result.compact).toEqual('73282932000074');
+  test.each([
+    '73282932000074',
+    '356 000 000 09075',
+    '35600000000048',
+    '35600000049837',
+  ])('validate:%s', value => {
+    const result = validate(value);
+
+    expect(result.isValid).toEqual(true);
   });
+  // it('validate:73282932000074', () => {
+  //   const result = validate('73282932000074');
+
+  //   expect(result.isValid && result.compact).toEqual('73282932000074');
+  // });
 
   it('validate:12345678', () => {
     const result = validate('12345678');
@@ -20,8 +30,8 @@ describe('fr/siret', () => {
     expect(result.error).toBeInstanceOf(InvalidLength);
   });
 
-  it('validate:73282932000075', () => {
-    const result = validate('73282932000075');
+  test.each(['35600000049838', '73282932000075'])('validate:%s', value => {
+    const result = validate(value);
 
     expect(result.error).toBeInstanceOf(InvalidChecksum);
   });
diff --git a/src/fr/siret.ts b/src/fr/siret.ts
index 5d0c085..8cf3e16 100644
--- a/src/fr/siret.ts
+++ b/src/fr/siret.ts
@@ -3,7 +3,11 @@
  *
  * The SIRET (Système d'Identification du Répertoire des Établissements)
  * is a 14 digit number used to identify French companies' establishments
- * and facilities. The Luhn checksum is used to validate the numbers.
+ * and facilities. The Luhn checksum is used to validate the numbers (except
+ * for La Poste).
+ *
+ * Sources:
+ *   https://fr.wikipedia.org/wiki/Système_d'identification_du_répertoire_des_établissements
  *
  * ENTITY
  */
@@ -11,7 +15,7 @@
 import * as exceptions from '../exceptions';
 import { strings } from '../util';
 import { Validator, ValidateReturn } from '../types';
-import { luhnChecksumValidate } from '../util/checksum';
+import { luhnChecksumValidate, weightedSum } from '../util/checksum';
 
 function clean(input: string): ReturnType<typeof strings.cleanUnicode> {
   return strings.cleanUnicode(input, ' -/');
@@ -50,7 +54,16 @@ const impl: Validator = {
       return { isValid: false, error: new exceptions.InvalidFormat() };
     }
 
-    if (!luhnChecksumValidate(value)) {
+    if (value.startsWith('356000000') && value !== '35600000000048') {
+      const sum = weightedSum(value, {
+        weights: [1],
+        modulus: 5,
+      });
+      console.log('HERE', value, sum);
+      if (sum !== 0) {
+        return { isValid: false, error: new exceptions.InvalidChecksum() };
+      }
+    } else if (!luhnChecksumValidate(value)) {
       return { isValid: false, error: new exceptions.InvalidChecksum() };
     }