I think he was lucky no fans were around. Not only is his disguise anything but convincing, he is also walking right alongside Bill Bray, who was already a well-known figure back then. I mean, come on - he might as well have carried a huge billboard with an arrow pointing right at Michael saying:
"This is Michael Jackson."
I have translated the text into English, but please note that it has been a very long time since I was even remotely good at German - and bear with me if it is not perfect.
Monkeys do it for him.
With his "gorillas" (bodyguards) in tow, Michael walked to the gorillas in the Berlin Zoo.
Purple picture: A nervous Michael on the street. When he does not hide his face in a scarf, he always brings along a jacket to hide behind.
Lower right-hand corner: A walk in the Berlin Zoo. No one recognizes the disguised man. By his side his fatherly friend, Bill Bray. The people on the benches and walkways have no idea who is walking among them. His "gorillas" - the bodyguards - follow a few meters behind.
Dark sunglasses: "I don't like when people look into my eyes," Michael Jackson wrote in his biography Moon Walk.
Black baseball cap: Michael carries 40 caps in his luggage. This one has the capital letters N and Y, short for New York.
Bushy sideburns: A make-up artist glues the Elvis-like sideburns to Michael's face. Cost: 440 Deutsch Mark.
Fake teeth: A set of fake teeth hides Michael's bright smile. The prosthesis, which changes his face, is kept in a special suitcase containing his disguises.
Mustache: Half of the text is missing but I think it say that the mustache is made of real hair and that it has been made in Los Angeles.