Reports appeared in local media earlier in the month that a law had been approved to charge residents of the 4-million-strong region 20 euros for each grilling session beginning in June.
"We have repeatedly denied this information, which is nothing but an April Fool's Day joke. But we never imagined it would create such a fuss," said the press secretary of Wallonia's minister for agricultural, rural affairs, the environment and tourism.
The media had said the new law was needed as an environmental measure and cited experts as saying that between 50 and 100 grams of CO2, a so-called greenhouse gas, was emitted during barbequing. Scientists believe CO2 emissions are a major cause of global warming.
According to the allegations, helicopters, equipped with thermal sensors to detect burning grills, were to have monitored compliance with the new tax legislation.
April Fool's Day is celebrated in many countries April 1 by playing hoaxes and practical jokes on friends, enemies and neighbors. The practice is sometimes observed in mass media.
Belgian media was implicated in another practical joke last December when state television broke into its regular programming with a report that the Dutch-speaking half of the country, Flanders, had declared its independence and that the king and queen had fled.
Panic ensued, with frantic calls being placed by foreign embassies and Belgian citizens to the government demanding an explanation, and order was only restored when the state-owned RTBF television station admitted the report was a hoax.