PARIS (AP) _ A West German salesman who provided two East German agents with commercially available items including dictionaries and brochures was convicted Friday of spying for a foreign power.

A special court sentenced Klaus Tscheu, who has lived in France since 1966, to four years in prison with 18 months suspended. The seven-judge panel acquitted a co-defendant, Francoise Drouillaut.

During the two-day trial, Tscheu, 51, said all he furnished to two East German agents during contacts from May 1982 to May 1983 were items available commercially, such as a Franco-German dictionary of computer terms he bought in a book store and leaflets on office equipment.

He said he was paid about $2,550 for his services.

Tscheu told the court he ended his contacts after a fourth meeting in East Berlin. He was arrested by French secret agents a few weeks later.

Tscheu became involved with the German agents after placing an ad in a West German newspaper offering to act as a commercial representative in France. He said his own commercial ventures, such as selling Greek carpets, had been unsuccessful and he was in need of a job.

When he first met the agents, identified as Michael Neubus and Peter, they said he could represent them in France, selling porcelain and shirts. However, Tscheu admitted in court that the men appeared ''a little strange.''

In three meetings in East Berlin, they asked him to supply seemingly banal information such as details on modern office equipment, a civil aviation map and a Franco-German technical dictionary.

Tscheu told the court the material he provided was all available commercially.

''I was arrested,'' Tscheu said in testimony Thursday. ''But I'm not a spy and I never was. I was afraid.''

French agents were alerted by the husband of Ms. Drouillaut, who was Tscheu's mistress. They began investigating Tscheu and arrested him within weeks of his last trip to East Berlin.

Ms. Drouillaut's husband, a navigating engineer at a flight test center, became suspicious after she began asking him a series of questions. The questions came after Tscheu's contacts requested technical information on the aviation industry.

The husband allegedly wrote an anonymous letter to the local gendarmerie denouncing Tscheu as a spy.