Tman, I concur with Ethan Seven's assessment: if Copytrack is a German firm, and the photographer is German, and you have no business interests or any form of residency in Germany... well, there's really no case for them to make. Citing German law to a US citizen is about as valid and useful as a three-dollar bill.
There's an example of how attempts at extraterritorial justice can fail very, very badly. Not that long ago, LucasFilm took designer and propmaker Andrew Ainsworth to court, suing him for breaching their rights.
Back in 1976, Ainsworth was the London, England based creator of the Stormtrooper armour for the first Star Wars films; he sculpted the moulds that would be used to vacuum-form the individual pieces that would form the suit as a whole. Fast-forward to the early 2000's and Ainsworth discovers his orginal moulds, dusts them off, and starts selling sets of Stormtrooper armour to order via his website.
Lucasfilm took exception to this and sued Ainsworth in US federal court, and won a $20M summary judgement since Ainsworth did not defend the case... but Ainsworth's business was solely based in the UK, and he had no residency or other presence in the US, Lucasfilm was quite unable to collect their money. After all, the US civil courts have no real power over non-resident aliens.
The sole remaining option open to Lucasfilm was to sue Ainsworth in his home country - which they did - but, because of the differences between US and UK intellectual property laws, Lucasfilm lost their case, which was ruled on by the Supreme Court in the UK.
Ainsworth still trades to this day, with the sole consequence of his US judgement being that he can't ship his creations to anyone with a US zip code.
If you're interested in a longer read about this specific case, head to
https://www.bbc.co.uk/news/uk-12910683