The 68-year-old stood accused of paying his two grandchildren in return for sexual services, the daily newspaper L'Avenir Luxembourg reported earlier this Tuesday.
The grandfather's daughter reportedly alerted the authorities after discovering evidence of the abuse on her sons' phones.
The defendant was found guilty of indecent assault on a minor, debauchery, and incitement to prostitution. The court sentenced him to four years in prison.
Arlon's public prosecutor's had initially demanded a 10-year prison sentence.
