That's not actually the case under EC 1107/2006 (the EU law covering air travel by 'persons with reduced mobility'). There are two things to clarify here: who you need to complain about and who you need to complain to.

'Complaining about' first: EC 1107/2006 transfers the responsibility for handling of PRMs to the airport; outbound from point of arrival at the airport all the way up to the door of the aircraft and inbound from the door of the aircraft all the way to leaving the airport. So in the case we're discussing here Frankfurt Airport is at fault rather than Lufthansa (though a decent airline should be proactive in forwarding customer complaints about service received, they're the ones actually being charged for the service by the airport).

'Complaining to': EC 1107/2006 mandates that each nation designate both a complaints and an enforcement body to deal with failures to implement the requirements of the law. The UK split the role with the Equalities and Human Rights Commission being the complaints body and the CAA the enforcement body. I'm not sure how Germany allocated the role, but the enforcement body is apparently the Arbeitsgemeinschaft Deutscher Verkehrsflughäfen,
Gertraudenstr. 20
10178 Berlin
Tel : 030 - -31 01 18-0
Fax : 030 – 31 01 18-90
who should be able to tell you how to register a complaint.

I'm not really up on how implementation is going in countries other than the UK, but the suggestion seems to be that the UK has been better at publicising the new passenger rights and more proactive in enforcing them than is typical. The EHRC have a bunch of information on the revised legal situation at http://www.equalityhumanrights.com/y...gs/air-travel/ And while this is UK focussed remember that the rights apply to any flight within, into or out of the EU regardless of carrier or airport, the only thing that changes by nationality of airline/airport is who you need to complain to.

EC 1107/2006 itself is actually surprisingly concise and readable and well worth a look if you want to understand your rights -- or to print off a copy to wave under someone's nose The officially published text can be found here: http://eur-lex.europa.eu/LexUriServ/...01:0009:EN:PDF

We don't have a complete solution yet, and enforcement apparently varies, but the law has shifted considerably in our favour.