זה שער יפו?

The sign is extremely small and blurred in the image, even after zooming and enhancing. The text is not fully legible, but the shape and stroke pattern strongly suggest a standard Arabic prohibition sign of that era.

Based on its location (right at the narrow passage between the wall and the parking area) and the typical wording used in Jerusalem in the 1950s–60s, the sign most likely reads something along the lines of:

“ممنوع المرور”

(No passage / No entry)

or possibly:

“ممنوع مرور السيارات”

(No vehicle passage)

These were very common formulations on small black-background municipal signs around the Old City.

The letter shapes on the top line resemble the distinctive outline of ممنوع, and the lower line seems…