diff --git a/moto/kinesis/exceptions.py b/moto/kinesis/exceptions.py
index 981a577e..4ba4c8bf 100644
--- a/moto/kinesis/exceptions.py
+++ b/moto/kinesis/exceptions.py
@@ -16,4 +16,4 @@ class ResourceNotFoundError(BadRequest):
 class StreamNotFoundError(ResourceNotFoundError):
     def __init__(self, stream_name):
         super(StreamNotFoundError, self).__init__(
-            'Stream {} under account 123456789012 not found.'.format(stream_name))
+            'Stream {0} under account 123456789012 not found.'.format(stream_name))
diff --git a/moto/kinesis/responses.py b/moto/kinesis/responses.py
index fe57cbfd..43ed8b06 100644
--- a/moto/kinesis/responses.py
+++ b/moto/kinesis/responses.py
@@ -10,7 +10,7 @@ class KinesisResponse(BaseResponse):
 
     @property
     def parameters(self):
-        return json.loads(self.body)
+        return json.loads(self.body.decode("utf-8"))
 
     @property
     def kinesis_backend(self):