diff --git a/src/plyxproto/parser.py b/src/plyxproto/parser.py
index aabf2eb..f96125c 100755
--- a/src/plyxproto/parser.py
+++ b/src/plyxproto/parser.py
@@ -37,6 +37,7 @@
 from .helpers import LexHelper, LU
 from .logicparser import FOLParser, FOLLexer, FOLParsingError
 import ast
+import sys
 
 
 class PythonError(Exception):
@@ -155,7 +156,8 @@
 
     def t_error(self, t):
         print(("Illegal character '{}' ({}) in line {}".format(
-            t.value[0], hex(ord(t.value[0])), t.lexer.lineno)))
+            t.value[0], hex(ord(t.value[0])), t.lexer.lineno)),
+            file=sys.stderr)
         t.lexer.skip(1)