This is real chalk. Not a weird paint or new fangled anything. Just good ol' fashioned sidewalk chalk. Pretty much the same as you had as a kid, but nicer because they use silicone vaccuum molds to make it.
In our test it came off with a hose from a driveway & sidewalk pretty easily. We don't know how it would work with fresh paint. To be safe, you might try a inconspicuous corner, and make sure the paint is completely set.