When slightly changing your path within the lane you are taking, are you obliged to signal it earlier with an indicator?

According to Art. 22 para. 5 of the Road Traffic Act, a driver is only obliged to signal the intention to change lanes or direction. A slight course correction within the same lane (without crossing the lane markings visible on the roadway) is not considered either of those manoeuvres. Therefore, you are not obliged to use your indicator in the described situation.