French President Francois Mitterrand, concerned about a technological challenge from the United States and Japan, today formally launched a European high-technology project that covers areas similar to the Reagan administration's Strategic Defense Initiative, popularly known as "Star Wars."

Addressing a conference of ministers and industrial leaders from 17 European countries, Mitterrand announced that France would make an initial contribution next year of about $115 million to the project, which is known as Eureka. This marks the first pledge of government money to the French-sponsored research program, which is still in the planning stages.

The Eureka project is regarded by French officials as a way of galvanizing governments and industries across Western Europe to coordinate efforts on scientific research. It has succeeded in generating considerable interest since it was proposed three months ago by Mitterrand.

Today's conference in Paris was attended by representatives of all 10 European Community countries plus Spain, Portugal, Norway, Austria, Sweden and Finland.

In his speech, Mitterrand said that the principal aim of Eureka is to assure "the technological independence of Western Europe." French officials have denied, however, that Eureka is designed as direct competition for "Star Wars."

Unlike SDI, which is intended to result in the construction of a space-based defense system against nuclear missiles, Eureka is primarily a civilian project. The two programs will, however, have several common areas of research such as in laser beams, high-speed computers and artificial intelligence.

Acknowledging that the Eureka research could be put to dual civilian and military use, a senior French official said that restrictions on the transfer of new technology would limit participation in the project to West European countries. Several communist countries, including Bulgaria, have expressed interest in participating.

After a meeting with Mitterrand earlier this month to discuss Eureka and "Star Wars," Vice President Bush said that there is no "incompatibility" between the two projects. He added that there is less difference between the United States and France than appeared to be the case after the Bonn economic summit last May, when Mitterrand complained that the Reagan administration was treating Europeans like "subcontractors."

Although Mitterrand ruled out formal French participation in "Star Wars," U.S. officials have been told that individual French firms will be allowed to bid for research contracts.

The participants in today's conference appeared to have different ideas on the future shape of Eureka. Britain, in particular, is opposed to the spending of large amounts of government money and has proposed instead practical agreements on common European products and fiscal encouragement for firms producing for the European market.

The question of funding Eureka is crucial, given the budgetary constraints faced by European governments and firms at a time of economic difficulties. One of the attractions of "Star Wars" for many European high-technology companies is the prospect of securing a chunk of the $26 billion, which the Reagan administration has already earmarked for the project.

In his speech, Mitterrand said that the French contribution of about $115 million could be increased according to the success of Eureka.

France's Matra company has signed agreements with Norsk Hydro of Norway on the development of high-speed computers and with SGS of Italy on work with integrated circuits.

The four largest European electronics groups have announced that they will undertake joint studies.