For those who are in the lucky position to get their working time in the film team -- and thus also overtime -- paid according to the tariff, there has been (at least) one app for iOS for logging working time for some time, Überstunden of Rahmenfutter (for 5.49 Euro; from iOS 10.0). This is specially adapted to the needs of film teams and offers, among other things, an export of time sheets, master sheets, etc. to the responsible production department.
Since April TimeSheet is a similar app for recording working time for Android (from v4.4), including time sheet export. Here also, for the recording of overtime, the special features of the collective agreement for permanent film and television employees (TV FFS, valid from 01.04.2016 and the agency table from 01.01.2017) were observed. However, this app is still under development and has a few additional functions in comparison. It costs 5,99 Euro.