Germans' suspicions that the advent of euro notes and coins in January 2002 pushed up prices have been proved true.
A Bundesbank study showed that firms offering such services as haircuts and dry cleaning exploited the change - but lost sales as a result.
Germans have long been cynical about the switch, dubbing the new currency the "teuro" - a play on "teuer", the German for "expensive".
Similar concerns have been registered in most other eurozone countries.
Earlier this month, an Italian court forced a coffee bar near Rome to compensate a customer for raising the price from 1,500 lire (77 euro cents) to 1 euro when the changeover happened on 1 January 2002.
In Greece, consumers have held "buy-nothing days", in retaliation at what they claim are massive price rises.
Prices rises in Germany after the introduction of euro cash:
Cinema tickets: 2.3%
Dry cleaners: 2.5%
Bait and switch
The Bundesbank said not all German businesses took advantage of the currency switch.
Overall, prices rose by just 0.3%.
But service providers cashed in, with hairdressers hiking prices on average by 1.9%, and dry cleaners by 2.5%.
But the bank said the culprits had often paid for their opportunism.
In many cases, prices had been held at post-introduction levels ever since, after shoppers stayed away.
Cinemas, which raised ticket prices by 2.3%, saw turnover fall 12.5% in the first six months of 2003 compared with the previous year - although the continuing difficulties in the German economy may also have played a role.
And the Bundesbank also acknowledged that official attempts to play down the gains had been widely disbelieved by a sceptical German public.
"Official explanations of the limited effect of the introduction of euro cash have often encountered incomprehension on the part of the public," the report said.