So they can get DNA from someone suspected of “theft or property damage”??
So, in this case, the fact that persons were suspected of the crime meant that they could get their DNA? Turns out you don’t even need the database then! You can just get the DNA on-demand.
That's about the size of it. Oddly enough, whether police can collect DNA from arrestees was the main legal issue in a moot court competition that I participated in some years back. The Supreme Court eventually took up that issue (in case originating in Maryland) and found that a DNA swab at the time of arrest was constitutional (see here for a summary: https://www.oyez.org/cases/2012/12-207).
It's not clear to me from the original article here whether France's system requires an actual arrest before they can demand that a person give DNA.