A French teacher walking home from a sidewalk cafe in Moslem-controlled west Beirut was kidnaped by gunmen last night, becoming the latest Western European victim of lawlessness in Lebanon's chaotic capital.

Security sources said Michel Brian, 45, a teacher at the College Protestant Francais, was seized near his apartment building on Hamra Street. No group has asserted responsibility for his kidnaping.

Brian, who has been in Lebanon since 1981, is the 10th French citizen who has been seized or vanished here in the past two years. The captives also include a dozen other foreigners, among them Americans, Britons and Italians, most of them apparently held by Shiite Moslem militants.

On March 28, two British teachers, Philip Padfield and Leigh Douglas, disappeared after leaving a west Beirut pub. They and Brian were among a shrinking group of westerners who still dared go out at night to restaurants and cafes -- activities most Lebanese residents gave up long ago.

Last month, Islamic Jihad, a militant Shiite group about which little is known, asserted that it had executed a French captive, Michel Seurat, as a spy. A few days later, a four-man French television crew was abducted.

The targeting of foreigners employed at Beirut's many schools, however, has fueled concern about the future of academic standards in west Beirut and the safety of remaining foreigners.

The British Embassy yesterday telephoned Britons still in west Beirut, including journalists, and repeated previous advice against traveling or living here except for compelling reasons.

Monday, students and faculty at the American University of Beirut held a one-day strike to protest the kidnapings.

The American University was an early target of the militants. David Jacobsen, director of its hospital, and Thomas Sutherland, dean of its agricultural engineering school, both Americans, were kidnaped last year and are still being held. In 1984, the university's acting president, Malcolm Kerr, was killed on the campus, and in 1982, his predecessor, David Dodge, was kidnaped and held for a year.

Islamic Jihad asserts that it is holding the missing university officials, along with at least two other Americans -- Associated Press Beirut bureau chief Terry Anderson and the Rev. Lawrence Jenco, director here of Catholic Relief Services.

In addition, American University librarian Peter Kilburn disappeared in west Beirut in 1984, but he has not been mentioned by Islamic Jihad.