Red Lunar New Year gift envelopes that look like Vietnamese currency may be trendy right now, but Vietnam’s central bank is absolutely furious about them.

The State Bank of Ho Chi Minh City has requested government bodies to take action against individuals who sell envelopes that resemble the Vietnamese currency, as the production and distribution of such envelopes is illegal, VN Express reported.

Envelopes are on sale that bear the designs of Vietnamese bills with denominations from 50,000 to 500,000 Vietnamese dong. Tet—the Lunar New Year—is the country’s longest and most important holiday, when millions of lucky money envelopes are used to give cash gifts to friends or family members.

The production and sale of lucky money envelopes that bear a close resemblance to banknotes without the State Bank’s permission is illegal. Offenders are punishable with a maximum fine of VN80 million (US$3,451).

Tet will fall on February 5 this year.