The aircraft had the default German Sea-camouflage of grey fuselage and upper-sides covered with a pattern of hexagons in three colours applied

Scheme Colour name RAL Humbrol XtraColor Vallejo Model Color Vallejo Model Air
Standard #1 Sides of fuselage; floats; struts Light grey 7030   X257    
Upper sides: hexagonal (sides 15 cm) camouflage-pattern Blue grey          
Brown grey          
Green grey          

Check www.paint4models.com for an extensive conversion table with lots of colour and paint systems.