The Tokyo Metropolitan Government announced Monday that it will classify the erotic Younger Sister Paradise 2 as a "harmful publication" to minors, the first time the designation has been made since 2011, when restrictions were tightened on the sale of sexual manga and anime.

According to The Tokyo Reporter, Younger Sister Paradise 2 is Sekizai Mikage's adaptation of an adult video game about a boy who's propositioned by his five younger sisters. It was published last month by Kadokawa Shoten.

Because of the designation, customers under the age of 18 won't be able to buy, rent or browse the manga, which must be stocked in an area restricted to adults. Retailers who violate the ordinance face a fine of 300,000 yen (about $2,940 U.S.).

The 2011 revisions to the Youth Healthy Development Ordinance were opposed by many artists and publishers, including Kadokawa Shoten, who viewed the further restrictions as an infringement upon their freedom of expression. While bookstores were already required to move to an adult section any content that might “stimulate a reader’s sexual feelings,” the amended ordinance now encompasses manga and anime that “significantly and unjustly glorify and exaggerate" sexual activity considered a deviation from social norms.