The Senegal-born chemist became one of Germany's first black lawmakers in when he and another black candidate were elected to the federal parliament in 2013. Diaby has been the subject of racist slurs and and his office window has been smashed in the past.
German Foreign Minister Heiko Maas, who like Diaby belongs to the center-left Social Democratic Party, called the window incident “repulsive and cowardly” and voiced his support for the lawmaker. Far-right extremists have stepped up their verbal and physical attacks against German politicians in recent years.
Last June, a member of Chancellor Angela Merkel's party was killed by a neo-Nazi with a long history of violence. Months later, a long-time mayor in the eastern state of Saxony resigned following a campaign of threats and intimidation from the far right.