From the throw it and see if it sticks school of taxation, the DPW is invoking a previously little-known fee for resident's own improvements on public sidewalks... like putting plants and even trees in the empty dirt between the sidewalk and the curb. Of course, they're being entirely-even handed about it, taxing everyone from elderly stoke victims to plutocrats in the Marina.
Presumably since all our houses are worth millions, we're not going to notice.
All this and more from Matt Lanning. Matt is a very successful San Francisco realtor, and his blog is picking up steam. Sadly, CurbedSF expects this may have to do with there being less real estate to deal, but he's worth reading.