Is a permit required for balcony extension?

We have bought a house in BW and would like to enlarge the balcony. So far, it measures 5.25 x 1.50 m (see attachment). The extension is planned to be approximately 5.25 x 4 m. The renovation will probably be done independently without an architect. Is a permit required for this or what does it depend on? What costs would we incur if a permit is necessary?

From the gut, I would say that you definitely need a permit for that and also a structural engineer who calculates for you whether and how something like that can be built.

The attachment does not tell everything. Basically, I also say that at least a structural engineer is necessary. But it is also important whether you are coming into any boundary areas of the property with it, possibly exceeding building limits and such things.

In our country, everything over 3 meters must be approved (NDS).