The dpa news agency reported that the two defendants, aged 30 and 31, were convicted Wednesday by an administrative court in the southern city of Augsburg and each fined about 5,000 euros ($5,885).
The younger man, not identified in line with privacy laws, told the court that he used a high-pressure water jet to draw the swastika as a "stupid joke" at a garden party.
The homeowner said he hadn't bothered to remove it for several months, until police started investigating the case in January.
The judge said there was no evidence the two had neo-Nazi leanings.
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