For the sign of the Παπαβασιλοπουλος (Papavasilópoulos) menswear shop, an adaptation of Zipper for the Greek script is used, which seems to be a popular option for menswear stores in the Omonoia district, see the Arnokouros shop sign.
This is the first lowercase adaptation of Zipper that I have encountered. The lowercase π is the uppercase form at a smaller scale. Since it has no affinities to any letterforms of Zipper for the Latin script, it seems to be originally designed. Moreover, the π is different from other adaptations of Zipper, e.g in the logo of Πολιτιστική magazine. The lowercase λ (λαμδα, lamda) is a mirrored Latin h.