Harlequin & Columbine

[ChocClare]

I read a children's book in the late 70s about a boy whose village was visited by a travelling Commedia dell'Arte show. Harlequin and the various clowns helped him to ....???? get rid of the Germans I THINK (can't honestly remember, but I have it in mind that it is set during the first or second world war). They then move on - the implication being that they are mythical creatures come to life to save the village. You're probably not that excited from my summary, but it was a really fabulous book and I'd love to read it again. Does it ring any bells with anyone?