AFAIK there’s no official ruling in St. Louis that say any structure must be shorter than the Arch, but there’s been nothing built that’s as tall, either.
I’m pretty sure that the Tour Montparnasse is the only building in Paris proper that’s as tall as the Eiffel Tower. There is a huge, Canary Wharf-esque office development to the northwest of the city at La Défense.
Builders in Philadelphia used to go by a sort of gentlemen’s agreement that no building could be higher than William Penn’s hat. Philadelphia’s rather, umm, massive City Hall, you see, is crowned by a tower, on top of which is a large statue of William Penn tipping his three-cornered hat. This limited the height of buildings to 500-odd feet.
Then in the mid-'80s the builders of One Liberty Place exceeded that limit by about 400 feet, and the gentlemen’s agreement evaporated, not so much like dew in the morning sunlight as like dew in the path of an oncoming flame thrower.
I liked it better with the gentlemen’s agreement.
Thus bringing about the Curse of Billy Penn: After One Liberty Place went up in 1987, no Philly sports team won a chamapionship. That is, until the even taller Comcast Center was built in 2007, with it’s own statue of Penn topping it off. The following year, the Phillies won the World Series.