The 461 hectare FFH area Pätzer Hintersee corresponds in its delimitation to the NSG of the same name except for small deviations in the east. It is located southeast of Bestensee and southwest of Pätz. In the west, the protected area borders on the Berlin-Cottbus railway line.
The protected area includes the entire water and bank silting moor area of the Pätzer Hintersee with extensive lowland forests, intermediate moorland and reed beds. In the south there is the Merkhorst, an elevation planted with mixed deciduous forest. In the peripheral areas there are extensively used grassland areas. In the transition area from the grassland lowlands to the wooded slopes as well as on individual small knolls there are small sand dry lawns and dry edges. The core areas of the protected area include the lime-rich silting moor areas with small sedge and flat moor meadows that adjoin the water and reed areas of the Hintersee in the southwest. Willow bushes form the transition areas between the silting bog areas and the wet meadows. Formations of rich to poor wet meadow areas alternate with tall herbaceous areas.