diff --git a/mpqp/core/circuit.py b/mpqp/core/circuit.py
index 67833aae..4dd2cb3a 100644
--- a/mpqp/core/circuit.py
+++ b/mpqp/core/circuit.py
@@ -358,8 +358,9 @@ def nb_qubits(self) -> int:
 
     @nb_qubits.setter
     def nb_qubits(self, nb_qubits: int):
-        self._user_nb_qubits = nb_qubits
-        self._set_nb_qubits_dynamic(nb_qubits)
+        if self._user_nb_qubits is None or self._user_nb_qubits != nb_qubits:
+            self._user_nb_qubits = nb_qubits
+            self._set_nb_qubits_dynamic(nb_qubits)
 
     def _set_nb_qubits_dynamic(self, nb_qubits: int):
         if not hasattr(self, "_nb_qubits") or nb_qubits != self._nb_qubits:
diff --git a/mpqp/tools/display.py b/mpqp/tools/display.py
index ea9540ae..a5fc61d1 100644
--- a/mpqp/tools/display.py
+++ b/mpqp/tools/display.py
@@ -5,13 +5,14 @@
 
 import numpy as np
 import numpy.typing as npt
+from numbers import Complex
 
 if TYPE_CHECKING:
     from sympy import Expr, Basic
 
 from typeguard import typechecked
 
-from .generics import Matrix, Complex
+from .generics import Matrix
 
 
 @typechecked
diff --git a/mpqp/tools/generics.py b/mpqp/tools/generics.py
index d5fafa13..321b6654 100644
--- a/mpqp/tools/generics.py
+++ b/mpqp/tools/generics.py
@@ -63,11 +63,6 @@
 """Type alias denoting all the matrices we consider (either matrices of complex 
 or of ``sympy`` expressions, given to ``numpy`` as objects)"""
 
-Complex = Union[complex, float, int]
-"""Type alias representing any scalar value that can be treated as a complex number.
-(either Python `complex` numbers or Real numbers (`float` or `int`).
-"""
-
 
 @typechecked
 def flatten_generator(lst: ArbitraryNestedSequence[T]) -> Iterator[T]: