The royal couple was greeted by hundreds of enthusiastic well-wishers in Nuremburg, who didn't seem to notice the unusual design; however, photographs and comments about the offending coat soon began to be posted on social networks.
"A grey coat can provide a lot of attention – particularly when swastika-like symbols are visible," German newspaper Focus reported.
Die Welt noted that the coat is a favorite of Queen Maxima, who wore the same garment, designed by Dutch-Danish designer Claes Iversen, on a state visit to Denmark last year.
'Swastika pattern on her coat: Queen Maxima causes outrage in Franconia!' Bild reported.
King Willem-Alexander succeeded to the throne in 2013 after his mother Princess Beatrix abdicated, having reigned since 1980. His wife Queen Maxima is from Argentina, and is the daughter of former Argentinian politician Jorge Zorreguieta.