Posting an article I wrote last year for Bloomberg BNA entitled, International Ethics & Independence Body Revises Standards for Inducements, available for download below. This provision, which appears in the International Code of Ethics for Professional Accountants (including International Independence Standards) issued by the International Ethics Standards Board for Accountants (IESBA), became effective with the IESBA's newly restructured and revised Code, on June 15, 2019.
For additional information about the inducement standards see https://www.ifac.org/system/files/publications/files/Basis-for-Conclusions-Inducements.pdf.
By the way -- a new electronic version of the IESBA Code ("e-code") will be launched later this month, so stay tuned!