diff --git a/jedi/evaluate/analysis.py b/jedi/evaluate/analysis.py
index a7c4c441..8273df3e 100644
--- a/jedi/evaluate/analysis.py
+++ b/jedi/evaluate/analysis.py
@@ -15,6 +15,7 @@ CODES = {
     'type-error-too-many-arguments': (5, TypeError, None),
     'type-error-too-few-arguments': (6, TypeError, None),
     'type-error-keyword-argument': (7, TypeError, None),
+    'type-error-multiple-values': (8, TypeError, None),
 }
 
 
diff --git a/jedi/evaluate/param.py b/jedi/evaluate/param.py
index d12c611e..172a571e 100644
--- a/jedi/evaluate/param.py
+++ b/jedi/evaluate/param.py
@@ -1,5 +1,6 @@
 import copy
 
+from jedi._compatibility import unicode
 from jedi.parser import representation as pr
 from jedi.evaluate import iterable
 from jedi import common
@@ -37,13 +38,21 @@ def get_params(evaluator, func, var_args):
         while key:
             keys_only = True
             try:
-                key_param = param_dict[str(key)]
+                key_param = param_dict[unicode(key)]
             except KeyError:
                 non_matching_keys.append((key, value))
             else:
-                keys_used.add(str(key))
-                result.append(_gen_param_name_copy(func, var_args, key_param,
-                                                   values=[value]))
+                k = unicode(key)
+                if k in keys_used:
+                    print(keys_used, unicode(key), value)
+                    m = ("TypeError: %s() got multiple values for keyword argument '%s'."
+                         % (func.name, k))
+                    analysis.add(evaluator, 'type-error-multiple-values',
+                                 var_args, message=m)
+                else:
+                    keys_used.add(k)
+                    result.append(_gen_param_name_copy(func, var_args, key_param,
+                                                       values=[value]))
             key, value = next(var_arg_iterator, (None, None))
 
         keys = []
@@ -93,7 +102,7 @@ def get_params(evaluator, func, var_args):
 
         # Now add to result if it's not one of the previously covered cases.
         if not has_default_value and (not keys_only or param.stars == 2):
-            keys_used.add(str(key))
+            keys_used.add(unicode(param.get_name()))
             result.append(_gen_param_name_copy(func, var_args, param,
                                                keys=keys, values=values,
                                                array_type=array_type))
diff --git a/test/static_analysis/arguments.py b/test/static_analysis/arguments.py
index 07d3f766..bec40ee5 100644
--- a/test/static_analysis/arguments.py
+++ b/test/static_analysis/arguments.py
@@ -14,7 +14,7 @@ simple(1, 2)
 
 
 def nested(*args):
-    # TODO: shoult not be her but in line 17
+    # TODO: should not be here, but in line 17
     #! 13 type-error-too-few-arguments
     return simple(*args)
 
@@ -41,9 +41,7 @@ def two_params(x, y):
 two_params(y=2, x=1)
 two_params(1, y=2)
 
-# The next two statements should generate errors. Basically it should generate
-# something like `TypeError: x() got multiple values for keyword argument 'a'`.
-# For now however, any error should be fine.
+#! 10 type-error-multiple-values
 two_params(1, x=2)
 #! 17 type-error-too-many-arguments
 two_params(1, 2, y=3)
diff --git a/test/test_integration.py b/test/test_integration.py
index 78a1af43..237e823e 100644
--- a/test/test_integration.py
+++ b/test/test_integration.py
@@ -26,8 +26,8 @@ def assert_static_analysis(case, actual, desired):
     d = set(desired)
     assert actual == desired, """
 Test %r failed.
-too much = %s
-missing  = %s
+specified, not raised = %s
+missing = %s
 """ % (case, sorted(d - a), sorted(a - d))