If you do not comply exactly with the building regulations, it becomes a normal building permit procedure. Then the neighbors must be informed, as they can theoretically object to an issued building permit.
This statement is not correct. A building permit can also be sought without deviations from the building regulations or development plan.
The difference between the exemption procedure and a "real" building permit is therefore not whether the neighbor (all neighbors) have to agree or not.
This difference only refers to whether the architect/building owner takes responsibility for compliance or whether the authority checks it.
We built with a building permit, even violated the development plan in several points, but did not have to ask any neighbors; they were not even informed, neither by the authority nor by us, because these points did not affect any neighbor.