It happened while he was greeting people in the crowd Tuesday.
From Aleteia:
Unable to read lips, we nevertheless get the impression that His Holiness Pope Francis has made it clear that there is a line, and it has been crossed.
UPDATE: From our Spanish edition, we get a translation:
โยกPor favor! ยฟQuรฉ te pasรณ? ยกNo seas egoรญsta! ยกNo seas egoรญsta!โ
โPlease! What is happening to you? Donโt be selfish! Donโt be selfish!โ
See below.