Paintings of children trying to have fun when the grownups aren’t looking. Belgian. Franz Verhas, artist (1827-1897). Painted many portraits and genre scenes.

"The Lion." 1874.
“The Lion.” 1874. Oil on canvas. Collection of the the Museum of Fine Arts, Ghent. In the public domain in the United States it was published before January 1, 1924. via https://commons.wikimedia.org/wiki/File:Franz_Verhas_(1832-1894)_De_leeuw_(1874)_MSK_Gent_22-11-2015_11-58-03.JPG
"La lecture au salon." 1850-1894.
“La lecture au salon.” 1850-1894. Oil on canvas. In the public domain in the United States because the artist has been dead over 70 years. via https://commons.wikimedia.org/wiki/File:Frans_Verhas_-_Reading_in_the_living_room.JPG
"The Master Painter." 1877.
“The Master Painter.” 1877. Oil on canvas. Collection of the Museum of Fine Arts, Ghent. In the public domain in the United States it was published before January 1, 1924. via https://commons.wikimedia.org/wiki/File:Jan_Verhas_-_The_master_painter.jpeg
"The Broken Flower Pot." 1876.
“The Broken Flower Pot.” 1876. Lithograph. Image © 2019 – WorthPoint Corporation. Fair use license. via https://www.worthpoint.com/worthopedia/jan-frans-verhas-broken-flower-pot-537812522