give it a G , less chances for a fancy ramp check.
in germany a flight plan is needed for international flights , VFR night or IFR operation- domestic VFR day basicly does not need any flight plan, commercial or not.
exeptions from this are commercial photographic or laserscanning flights with specially equipped aircraft from high altitudes- in this case also fill a plan with the permission number and the area you fly in the remarks , beyond this you nevertheless have to coordinate and inform the supervisor of the radar area you fly in.
another exeption are training approaches on high density airports , here you have to inform and coordinate with the app supervisor as well.
beyond this hardly anybody cares what is filled in this item- the decision if this is a private , commercial or training flight is based on other factors should it become a question of interest.
cheers !