__new__?

noinit.py

class C:
    def __new__(cls, *args):
        print("C.__new__")
        return super().__new__(cls)

class D:
    pass

C(1,2,3)
D(1,2,3)
# Outputs:
# C.__new__
# Traceback (most recent call last):
#   File "test.py", line 9, in <module>
#     D(1,2,3)
# TypeError: object() takes no parameters

withinit.py

class C:
    def __new__(cls, *args):
        print("C.__new__")
        return super().__new__(cls)

class D:
    pass
    def __init__(self, a, b, c):
        print("D.__init__")

C(1,2,3)
print("between")
D(1,2,3)
# Outputs:
# C.__new__
# between
# D.__init__