Flachenseiffen was formerly part of the German Empire. In the German Empire, the place was called Flachenseiffen.
The place is now called Płoszczyna and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Flachenseiffen | German Empire | Löwenberg i. Schles. | 1939 |
| Płoszczyna | Under Polish administration | Lwówek Śląski | 1945 |
| Płoszczyna | Poland | Jelenia Góra | 1992 |