Karel is often used as a masculine name, but can also be used as a feminine name. Some feminine forms include: Karel, Karelle, Karèle, Karrelle, Karelle etc.
A famous bearer is Karel Èapek, my dear author. His works are for example "War With the Newts", "How it is Made", "Krakatit", "Stories from a Pocke"t and many others.
Karel Appel (1921-2006) was a Dutch abstract painter, sculptor, printmaker, ceramicist, designer and writer, regarded as the most powerful of the post-war generation of Dutch artists.