Really? That seems very odd to me. In the UK I've never put my birth date, gender or photo on a CV and you're advised not to, unless you're applying to be like a model or something where I guess gender and photo is needed.
When I was in the 6th Form in the UK we were told we had to include a photo with CVs. Another reason you should never take careers advice from someone who became a careers advisor!
Immigration is still a pretty new thing for most of central Europe.
There weren't a significant number of visibly-foreign immigrants in Germany till the 60s or 70s and it took a couple more decades before those were seen as anything other than 'temporary guest workers'.
The UK and France (and even more so the US and other "New World" countries) had at least a few decades head-start for culture to get around the idea of immigration.
Depends on where you work. Anything influenced by the English-speaking world (IT, multinationals) – never attach a photo. A small local company – always attach a photo. Anything else – good luck deciding what to do.
Not really anymore, the latest version of the DIN norm on CVs has no photo or birthdate anymore, and in some states, it’s being discussed to ban it even.
On the whole I hate the practice, but you have to consider cultural norms when doing the job-hunting dance.