Look at the Collectobil site under rescue theme for items #3526 & #3525. 3525 was available from 1981 thru 1987, & 3526 was available from 1981 thru 1984. Both items shared the same decal sheet during production, & the 4 section decal was shown used on both in the pictures. I really like the 3525, & 3526 version fire trucks, but they are rare, & expensive to obtain.
Ah, okay, as you mentioned it is recognizable on the small collectobil pics (and a little bit less recognizable in the collector). And indeed it was quite at the end of my active Playmobil playing phase (never have owned one) and before my collecting period.
The logo is quite interesting because I have never seen it in Germany on rescue vehicles but it is used by firemen as sticker on their private cars and in case of promotion events of the fire rescue units as logo on flyers or presentation walls. I'm not sure if this is an international emblem, because so far I have only seen it in Germany, so I was even more surprised to see this on the custom scenery. Now having the information that's an original Playmobil part I do not wonder anymore.
Anyway, to come back to the photos again: what is under the green cover of the trailer at the background vehicle? A boat?