Actually it duplicates the reference on an element.

my_list = [[1]] * 3
print(my_list)
>>> [[1], [1], [1]]
my_list[0].append(2)
print(my_list)
>>> [[1, 2], [1, 2], [1, 2]]

But as you mentionned, there is no problem with primitive and immutable types: int, str, tuple, frozenset...

my_list = [1] * 3
print(my_list)
>>> [[1], [1], [1]]
my_list[0] += 1
print(my_list)
>>> [2, 1, 1]