Road sign indicates limits upon vehicle allowed to enter (north into parking area).

max-length: 5 metres / 16 feet,
sign also makes reference to vehicles of “3-5T” (unsure if unit is tons or tonnes), but is unclear if this is a max-weight limit or if the max-length limit applies only to vehicles within the specified range.

Included a photo, for clarity.

via StreetComplete 31.3

Attached photo(s):
https://westnordost.de/p/40108.jpg