Ladybug server's batman for child support!
This is an old one from before I had a A03 account so I don't know where I read it (a03, wattpad etc) so probably like 6+ years old fic.
Marinette knows she's batman's daughter sabine was an assassin (I think). One day either sabine or Tom (I think it was tom) gets sick, really sick. But a few months down the line Marinette over hears them discussing their finances and between operating the bakery paying for treatment and having to fight against (lilas) false accusation against Marinette and the bakery, between lawyers and days where the bakery has had to shut because of inspections etc moneys getting tight. Marinette confront her parents and offers her saving from MDC but even that would buy them a couple of extra months more.
After some time of stress, sleep deprivation, and overthinking, Marinette decides its time to get her child support so she does some research (I think makorov help here) so decides she's gonna server her dead beat bio father with 17+ year of child support plus emotional and mental damages.
Cut to gcpd roof top batsignal batman appears only for gordon to ask if he turn on the signal, ladybug appears from the shadows with a vanilla envelope, servers batman snap pic woth yoyo and disappears and chapter ends with someone making a joke that even the bat can't escape a court server/dead beat dad joke.