diff -r 7d90bf4780ff Lib/fractions.py
--- a/Lib/fractions.py	Mon Aug 22 18:07:02 2016 +0300
+++ b/Lib/fractions.py	Tue Aug 23 13:39:40 2016 +0300
@@ -81,7 +81,7 @@ class Fraction(numbers.Rational):
     __slots__ = ('_numerator', '_denominator')
 
     # We're immutable, so use __new__ not __init__
-    def __new__(cls, numerator=0, denominator=None, _normalize=True):
+    def __new__(cls, numerator=0, denominator=None):
         """Constructs a Rational.
 
         Takes a string like '3/2' or '1.5', another Rational instance, a
@@ -176,18 +176,16 @@ class Fraction(numbers.Rational):
 
         if denominator == 0:
             raise ZeroDivisionError('Fraction(%s, 0)' % numerator)
-        if _normalize:
-            if type(numerator) is int is type(denominator):
-                # *very* normal case
-                g = math.gcd(numerator, denominator)
-                if denominator < 0:
-                    g = -g
-            else:
-                g = _gcd(numerator, denominator)
-            numerator //= g
-            denominator //= g
-        self._numerator = numerator
-        self._denominator = denominator
+
+        if type(numerator) is int is type(denominator):
+            # *very* normal case
+            g = math.gcd(numerator, denominator)
+            if denominator < 0:
+                g = -g
+        else:
+            g = _gcd(numerator, denominator)
+        self._numerator = numerator // g
+        self._denominator = denominator // g
         return self
 
     @classmethod
@@ -457,17 +455,19 @@ class Fraction(numbers.Rational):
             if b.denominator == 1:
                 power = b.numerator
                 if power >= 0:
-                    return Fraction(a._numerator ** power,
-                                    a._denominator ** power,
-                                    _normalize=False)
-                elif a._numerator >= 0:
-                    return Fraction(a._denominator ** -power,
-                                    a._numerator ** -power,
-                                    _normalize=False)
+                    return _from_normalized(
+                                    a._numerator ** power,
+                                    a._denominator ** power)
+                elif a._numerator > 0:
+                    return _from_normalized(
+                                    a._denominator ** -power,
+                                    a._numerator ** -power)
+                elif a._numerator < 0:
+                    return _from_normalized(
+                                    (-a._denominator) ** -power,
+                                    (-a._numerator) ** -power)
                 else:
-                    return Fraction((-a._denominator) ** -power,
-                                    (-a._numerator) ** -power,
-                                    _normalize=False)
+                    raise ZeroDivisionError(f'{a!r} cannot be raised to a negative power')
             else:
                 # A fractional power will generally produce an
                 # irrational number.
@@ -491,15 +491,15 @@ class Fraction(numbers.Rational):
 
     def __pos__(a):
         """+a: Coerces a subclass instance to Fraction"""
-        return Fraction(a._numerator, a._denominator, _normalize=False)
+        return _from_normalized(a._numerator, a._denominator)
 
     def __neg__(a):
         """-a"""
-        return Fraction(-a._numerator, a._denominator, _normalize=False)
+        return _from_normalized(-a._numerator, a._denominator)
 
     def __abs__(a):
         """abs(a)"""
-        return Fraction(abs(a._numerator), a._denominator, _normalize=False)
+        return _from_normalized(abs(a._numerator), a._denominator)
 
     def __trunc__(a):
         """trunc(a)"""
@@ -641,3 +641,12 @@ class Fraction(numbers.Rational):
         if type(self) == Fraction:
             return self     # My components are also immutable
         return self.__class__(self._numerator, self._denominator)
+
+
+def _from_normalized(numerator, denominator):
+    self = super(Fraction, Fraction).__new__(Fraction)
+    assert type(numerator) is int is type(denominator)
+    assert denominator != 0
+    self._numerator = numerator
+    self._denominator = denominator
+    return self
diff -r 7d90bf4780ff Lib/test/test_fractions.py
--- a/Lib/test/test_fractions.py	Mon Aug 22 18:07:02 2016 +0300
+++ b/Lib/test/test_fractions.py	Tue Aug 23 13:39:40 2016 +0300
@@ -150,6 +150,8 @@ class FractionTest(unittest.TestCase):
         self.assertRaises(TypeError, F, "3/2", 3)
         self.assertRaises(TypeError, F, 3, 0j)
         self.assertRaises(TypeError, F, 3, 1j)
+        self.assertRaises(TypeError, F, 7, 3, 1)
+        self.assertRaises(TypeError, F, 7, 3, 0)
 
     @requires_IEEE_754
     def testInitFromFloat(self):