diff --git a/src/corelibs/string_handling/timestamp_strings.py b/src/corelibs/string_handling/timestamp_strings.py
index 68346de..ae3fea9 100644
--- a/src/corelibs/string_handling/timestamp_strings.py
+++ b/src/corelibs/string_handling/timestamp_strings.py
@@ -28,7 +28,7 @@ class TimestampStrings:
         self.time_zone = time_zone if time_zone is not None else self.TIME_ZONE
         try:
             self.timestamp_now_tz = datetime.now(
-                ZoneInfo(self.time_zone) if not isinstance(self.time_zone, ZoneInfo) else self.time_zone
+                ZoneInfo(self.time_zone) if isinstance(self.time_zone, str) else self.time_zone
             )
         except ZoneInfoNotFoundError as e:
             raise ValueError(f'Zone could not be loaded [{self.time_zone}]: {e}') from e
diff --git a/test-run/timestamp_strings/timestamp_strings.py b/test-run/timestamp_strings/timestamp_strings.py
index dcf8109..b4fd464 100644
--- a/test-run/timestamp_strings/timestamp_strings.py
+++ b/test-run/timestamp_strings/timestamp_strings.py
@@ -22,6 +22,9 @@ def main():
     print(f"TZ: {ts.time_zone} -> TS: {ts.timestamp_now_tz}")
     ts = TimestampStrings(ZoneInfo("Europe/Vienna"))
     print(f"TZ: {ts.time_zone} -> TS: {ts.timestamp_now_tz}")
+    custom_tz = 'Europe/Paris'
+    ts = TimestampStrings(time_zone=custom_tz)
+    print(f"TZ: {ts.time_zone} -> TS: {ts.timestamp_now_tz}")
 
 
 if __name__ == "__main__":
diff --git a/tests/unit/string_handling/test_timestamp_strings.py b/tests/unit/string_handling/test_timestamp_strings.py
index 433f11d..d9d0522 100644
--- a/tests/unit/string_handling/test_timestamp_strings.py
+++ b/tests/unit/string_handling/test_timestamp_strings.py
@@ -3,7 +3,7 @@ PyTest: string_handling/timestamp_strings
 """
 
 from datetime import datetime
-from unittest.mock import patch, MagicMock
+from unittest.mock import patch
 from zoneinfo import ZoneInfo
 import pytest
 
@@ -119,18 +119,55 @@ class TestTimestampStrings:
             assert ts2.time_zone == 'Europe/London'
             assert ts1.time_zone != ts2.time_zone
 
-    @patch('corelibs.string_handling.timestamp_strings.ZoneInfo')
-    def test_zoneinfo_called_correctly(self, mock_zoneinfo: MagicMock):
-        """Test that ZoneInfo is called with correct timezone"""
+    def test_zoneinfo_called_correctly_with_string(self):
+        """Test that ZoneInfo is called with correct timezone when passing string"""
+        with patch('corelibs.string_handling.timestamp_strings.ZoneInfo') as mock_zoneinfo:
+            with patch('corelibs.string_handling.timestamp_strings.datetime') as mock_datetime:
+                mock_now = datetime(2023, 12, 25, 15, 30, 45)
+                mock_datetime.now.return_value = mock_now
+
+                custom_tz = 'Europe/Paris'
+                ts = TimestampStrings(time_zone=custom_tz)
+                assert ts.time_zone == custom_tz
+
+                mock_zoneinfo.assert_called_with(custom_tz)
+
+    def test_zoneinfo_object_parameter(self):
+        """Test that ZoneInfo objects can be passed directly as timezone parameter"""
         with patch('corelibs.string_handling.timestamp_strings.datetime') as mock_datetime:
             mock_now = datetime(2023, 12, 25, 15, 30, 45)
-            mock_datetime.now.return_value = mock_now
+            mock_now_tz = datetime(2023, 12, 25, 15, 30, 45, tzinfo=ZoneInfo('Europe/Paris'))
+            mock_datetime.now.side_effect = [mock_now, mock_now_tz]
 
-            custom_tz = 'Europe/Paris'
-            ts = TimestampStrings(time_zone=custom_tz)
-            assert ts.time_zone == custom_tz
+            # Create a ZoneInfo object
+            custom_tz_obj = ZoneInfo('Europe/Paris')
+            ts = TimestampStrings(time_zone=custom_tz_obj)
 
-            mock_zoneinfo.assert_called_with(custom_tz)
+            # The time_zone should be the ZoneInfo object itself
+            assert ts.time_zone is custom_tz_obj
+            assert isinstance(ts.time_zone, ZoneInfo)
+
+    def test_zoneinfo_object_vs_string_equivalence(self):
+        """Test that ZoneInfo object and string produce equivalent results"""
+        with patch('corelibs.string_handling.timestamp_strings.datetime') as mock_datetime:
+            mock_now = datetime(2023, 12, 25, 15, 30, 45)
+            mock_now_tz = datetime(2023, 12, 25, 15, 30, 45, tzinfo=ZoneInfo('Europe/Paris'))
+            mock_datetime.now.side_effect = [mock_now, mock_now_tz, mock_now, mock_now_tz]
+
+            # Test with string
+            ts_string = TimestampStrings(time_zone='Europe/Paris')
+
+            # Test with ZoneInfo object
+            ts_zoneinfo = TimestampStrings(time_zone=ZoneInfo('Europe/Paris'))
+
+            # Both should produce the same timestamp formats (though time_zone attributes will differ)
+            assert ts_string.today == ts_zoneinfo.today
+            assert ts_string.timestamp == ts_zoneinfo.timestamp
+            assert ts_string.timestamp_file == ts_zoneinfo.timestamp_file
+
+            # The time_zone attributes will be different types but represent the same timezone
+            assert str(ts_string.time_zone) == 'Europe/Paris'
+            assert isinstance(ts_zoneinfo.time_zone, ZoneInfo)
 
     def test_edge_case_midnight(self):
         """Test timestamp formatting at midnight"""
diff --git a/uv.lock b/uv.lock
index bc1d46b..3753dc0 100644
--- a/uv.lock
+++ b/uv.lock
@@ -53,7 +53,7 @@ wheels = [
 
 [[package]]
 name = "corelibs"
-version = "0.24.1"
+version = "0.24.2"
 source = { editable = "." }
 dependencies = [
     { name = "jmespath" },