diff --git a/whispercpp.pyx b/whispercpp.pyx
index 24ea068..edb5849 100644
--- a/whispercpp.pyx
+++ b/whispercpp.pyx
@@ -16,11 +16,11 @@ cdef char* DEFAULT_MODEL = b'tiny'
 cdef char* LANGUAGE = b'fr'
 
 MODELS = {
-    'model_ggml_tiny.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-tiny.bin',
-    'model_ggml_base.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-base.bin',
-    'model_ggml_small.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-small.bin',
-    'model_ggml_medium.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-medium.bin',
-    'model_ggml_large.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-large.bin',
+    b'model_ggml_tiny.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-tiny.bin',
+    b'model_ggml_base.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-base.bin',
+    b'model_ggml_small.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-small.bin',
+    b'model_ggml_medium.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-medium.bin',
+    b'model_ggml_large.bin': 'https://ggml.ggerganov.com/ggml-model-whisper-large.bin',
 }
 
 def model_exists(model):