diff --git a/cyipopt/scipy_interface.py b/cyipopt/scipy_interface.py
index d9a7fd1..238a4e6 100644
--- a/cyipopt/scipy_interface.py
+++ b/cyipopt/scipy_interface.py
@@ -682,6 +682,8 @@ def _minimize_ipopt_iv(fun, x0, args, kwargs, method, jac, hess, hessp,
         tol = np.asarray(tol)[()]
         if tol.ndim != 0 or not np.issubdtype(tol.dtype, np.number) or tol <= 0:
             raise ValueError('`tol` must be a positive scalar.')
+        else:  # tol should be a float, not an array
+            tol = float(tol)
 
     options = dict() if options is None else options
     if not isinstance(options, dict):
diff --git a/cyipopt/tests/unit/test_scipy_optional.py b/cyipopt/tests/unit/test_scipy_optional.py
index 22ddc13..fbd0669 100644
--- a/cyipopt/tests/unit/test_scipy_optional.py
+++ b/cyipopt/tests/unit/test_scipy_optional.py
@@ -30,6 +30,22 @@ def test_minimize_ipopt_import_error_if_no_scipy():
         cyipopt.minimize_ipopt(None, None)
 
 
+@pytest.mark.skipif("scipy" not in sys.modules,
+                    reason="Test only valid if Scipy available.")
+def test_tol_type_issue_235():
+    # from: https://github.com/mechmotum/cyipopt/issues/235
+
+    def fun(x):
+        return np.sum(x ** 2)
+
+    # tol should not raise an error
+    cyipopt.minimize_ipopt(
+        fun=fun,
+        x0=np.zeros(2),
+        tol=1e-9,
+    )
+
+
 @pytest.mark.skipif("scipy" not in sys.modules,
                     reason="Test only valid if Scipy available.")
 def test_minimize_ipopt_input_validation():