At least 30 Breguet XIV A2/B2 served with Royal Hellenic Army Air Force in mixed French-Hellenic 522th and 523th Reconnaissance-Bomber Squadrons. This "wavy line" appears in several other aircraft, perhaps is some kind of camouflage for the roundel or marking the aircraft participated to Minor Asia Campaign, as written in text below XIVA2 drawing. From 1922 Breguet XIV flown from Sedes Airport near Thessaloniki for training and later used as advanced trainers for observers of Hellenic Army Air Force. Finally, withdrawn for service in October-November 1931.
http://www.haf.gr/en/mission/weapons/hi ... re_XIV.asp
Second aircraft appears also as XIVA2, but perhaps also -B2 painted like this, because only A2 appears in sources. The wavy line seem darker in second drawing, possible if this line painted in bases/field.