أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم نَهَى عَنِ النَّجْشِ ‏.‏

It was narrated from Ibn 'Umar that: the Prophet forbade artificially inflating prices. Translation Not Available

Book Ref: Sunan An Nisai Book 44 Hadith 4505
Web Ref:  Sunan An Nisai Vol 5 Book 44 Hadith 4509