Police in Chongqing have detained a man for five days for smoking in a wholesale market, a move they hope sets an example for others who may be tempted to break a new law.

"Before we would give them a warning or a fine, but we found that didn't work well," said police officer Xu Yuhang, who caught the 56-year-old man smoking in an evacuation stairway on Saturday.

The man, surnamed Zhao, is the first person detained under the new law, which bans people from smoking in areas considered to be a fire hazard.