diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,4 @@
 requests
 setuptools
 vcversioner
+chardet
diff --git a/swh/loader/npm/client.py b/swh/loader/npm/client.py
--- a/swh/loader/npm/client.py
+++ b/swh/loader/npm/client.py
@@ -7,6 +7,7 @@
 import logging
 import os
 
+import chardet
 import requests
 
 from swh.core import tarball
@@ -196,8 +197,10 @@
         # parse package.json file to add its content to revision metadata
         package_json_path = os.path.join(package_path, 'package.json')
         package_json = {}
-        with open(package_json_path, "r") as package_json_file:
-            package_json = json.load(package_json_file)
+        with open(package_json_path, "rb") as package_json_file:
+            package_json_bytes = package_json_file.read()
+            file_encoding = chardet.detect(package_json_bytes)['encoding']
+            package_json = json.loads(package_json_bytes.decode(file_encoding))
 
         # extract author from package.json
         author = extract_npm_package_author(package_json)