A court in Kenya's central county of Nyeri has convicted a trader for selling banned plastic bags, the country's Daily Nation reports.
Nancy Wangari Roberts can pay a fine of $500 (£386) or spend six months in prison.
She is among several traders who have reportedly been found to have flouted the 2017 law.
NYERI COURT orders trader to pay Sh50,000 fine or spend six months in prison for selling banned plastic bags.
8:32 AM - Feb 8, 2019
The ban on plastic carrier bags means that anyone found selling, manufacturing or carrying them could face fines of up to $38,000 or prison sentences of up to four years.
The government says the ban will help protect the environment.
But manufacturers of the bags have argued that thousands of jobs could be lost.
Several other African countries have outlawed plastic carrier bags, including Rwanda, Mauritania and Eritrea.
Kenya's ban is seen as one of the toughest in the world.