The mother of the boy, Berrin T., 48, and her partner Christian L., 39, will serve twelve-and-a-half-year and twelve-year prison sentences respectively for selling Berrin's son on the area of the internet that can not be accessed by search engines.
In a case that horrified Germany, the defendant Javier Gonzalez Diaz was convicted by the regional court in Freiburg of "14 counts of aggravated sexual assault, one count of rape and one count of bodily harm while making child pornography", judge Stefan Buergelin said.
The court ruled that the man, who had a previous conviction for child abuse, must remain in preventive custody after serving his sentence.
Six others are accused of being part of the paedophile ring in which the boy was abused.
As well as pimping out the child, the pair also abused the boy repeatedly over a two-year period, which counted towards 60 separate identified acts of abuse.
One of the convicted Germans, a 44-year-old man, was allowed to rape the boy but was stopped by his mother after he expressed his wish to kill him. It said the mother was aware from the start of the man's pedophile tendencies and previous conviction.
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The trial has also raised concerns that officials might sometimes wrongly presume that a woman is incapable of abusing her own child. The girl, who had mental health issues, had on several occasions been given to the 48-year-old woman by her mother to care for her.
Video footage catalogued the horror of the boy's abuse, which included him being tied up and subjected to verbal humiliation.
The case only came to light following an anonymous tip in September 2017.
The case has shocked German society - and local authorities have been accused of failing to protect the boy, who now lives with a foster family.
The couple must now pay €42,500 (£38,000; $49,200) in damages to the boy and to a three-year-old girl, who was also abused by them.