Bookmice

Bookmice is a children's television series about a public library secretly inhabited by three fun-loving mice. It is a spinoff of "The Magic Library". It would often also showcase Eastern European cartoons such as and others. The series originally aired on TVOntario in Canada.
Description.
Norbert, Zazi and Leon, three fun-loving mice, live secretly behind the walls of the neighborhood library. Only Lee, a lonely boy who has just moved into the area, and an interloping, decrepit cat know of the existence of the Bookmice. Later in the series, the mice are discovered by three new children, Alysha, Jason, and Luke, who become their secret friends. Humor, wonder, stories, music, and delightful animation are present in the everyday adventures of the mice, as they explore the wondrous world of books – and the library's many friends and activities. Along with encouraging a love of reading, programs promote social values, as children learn about helping others, the importance of honesty, and overcoming fears.