Warning: This post relates to suicide and feelings of depression

People in China are landing themselves in trouble with the authorities for sharing a joke online that relates to the recent stock market crash.

The photo of a piece of paper taped to a wall or door translates in English to:

Notice Recently due to the nosedive of the stock market, in order to prevent accidents, this has been temporarily locked. The opening times of the rooftop will depend upon when the stock market recovers.

The image and the notice's text have been shared thousands of times on Weibo, the Chinese version of Twitter, on other sites and in texts:

A text message that has been widely circulated:

公安部緊急通知: 全国所有大厦天台闸门立即上鎖! Urgent notice from the police department: Rooftop gates across the country must be locked at once!

But the "accidents" aren't too much of a stretch from reality: at least two recent suicides in China have been blamed on the stock market crash, which has lost $3.2 trillion (30 per cent of its value) in the last few weeks amid fears that the country's equity market bubble is unsustainable.

What's more, a joke can carry a high price in China, where censors strictly control what can be said.

Reuters reports that the authorities arrested a man on Sunday for "disorderly behavior" because he was allegedly talking about people in Beijing's financial district jumping off buildings in response to the stock market crash.

In 2013, authorities unveiled tough new measures to stop the spread of what the government calls "irresponsible rumors", which can be punished by up to three years in jail if unsubstantiated social media posts are reposted 500 times, or viewed 5,000 times.

The Chinese government is in no mood for jokes: regulators and financial institutions are currently trying to prop up the nation's two main share markets, amid fears that a meltdown would harm the country's economy, where annual growth is already running at a 24-year low.