French-German ventures raise eyebrows - as well as suspicion - in Europe. France and West Germany say their cooperative ventures will give new impulse to the ideal of a united Europe. But other Europeans mistrust the special relationship. They question French motives, and wonder if bilateral defense and economic councils will supplant NATO - or exclude the other Europeans.

In the days following their 25th-anniversary bash, France and West Germany are facing some cold stares from their European partners. Washington is more tolerant. France and West Germany keep telling their allies they are not seeking to form an ``axis'' or ``directorate'' to dictate policy for Europe. Nor do the bilateral Defense and Economic Councils and Joint Brigade they set up Friday, a quarter century after their post-war treaty of reconciliation, aim to exclude anyone else or supplant NATO.

Rather, both countries say their aim is to reactivate the idea of a united Europe and to build a sturdy defense ``pillar'' here to strengthen the whole transatlantic partnership. ``We want to be the motors for the process of European unification,'' wrote Chancellor Helmut Kohl in his statement about the anniversary.

But British Prime Minister Margaret Thatcher, Italian Foreign Minister Giulio Andreotti, and Dutch Defense Minister W.F. van Eekelen have expressed mistrust of the special relationship. The French and West Germans, dismiss these misgivings. Mr. Andreotti has domestic political reasons for his criticism, suggested a West German official, while ``Britain never gets on the horse until it's moving.'' Bonn and Paris therefore are trying to get the horse walking in hopes that London - and Rome and the other European allies - will then jump on, too.

The alternative, they contend, is no motion at all. In this context West German officials note three current prods to action:

The declared intention of the European Community (EC) to form a real common market by 1992.

American impatience with what is seen as an inadequate European contribution to the defense of Europe.

West German presidency of the EC from January to June of 1988.

The post-war ideal of a united Europe petered out in the 1950s, a West German diplomat noted. What is needed now, therefore, are the kind of practical steps that will provide a new impulse to integration.

And French-German cooperation could provide this impulse. The French-German Financial and Economic Council could, for example, harmonize French and West German economic and fiscal policy. This could lay the groundwork for pan-European economic coordination and eventually even a common currency, and, if the French have their way, a European central bank. The council will have only consultative and not policy-making powers and will meet at least four times a year. It will consist of the French and West German financial and economic ministers, the president of the Bank of France, and the president of the Bundesbank.

The diplomat admitted that harmonization will not be easy, even for the two nations alone. Their views on economic strategy differ sharply, with France, like the United States, pressing West Germany to stimulate its economy. But the diplomat said changes in French economic policy over the past eight years have already gone far to bring together Paris and Bonn.

Europe's common defense is also served by French-German military cooperation, the two nations maintain. They contend that the result serves the common European interest, whatever the divergent motivations of the two. The French, fearing both a West German urge to neutrality and American disengagement, want to anchor Bonn to the West and take out insurance against any eventual American withdrawal. In addition, the very poorly equipped French Army would like to plug into the superb equipment of the West German Army.

The West Germans are careful to not raise the taboo of bringing France back into the integrated NATO command which President Charles de Gaulle abandoned 20 years ago. Rather, West Germany wants to bind Paris ever more closely to common NATO operations. Bonn therefore seeks to institutionalize France's tacit cooperation with NATO in recent years in joint French-West German exercises through the new bilateral Security Council and through a drive for ``interoperability'' in the two armed forces in ammunition, communications, fuel, and other essentials. On this basis they have carefully drawn their own participants in the new joint brigade from the territorial rather than the regular Army, to avoid removing any troops from the NATO command. They have also persuaded France that the only ``interoperability'' that would make sense is compatibility with NATO standards.

Under this arrangement, the defense council will have a tiny permanent secretariat in Paris. And the council of the foreign and defense ministers, the West German chancellor, and the French President and premier, along with their top military commanders, will assemble at least twice a year in addition to other bilateral and multilateral meetings. With this institutionalization, the West Germans hope to convince both Washington and Moscow that Europe is serious about its own defense.

The West Germans are finding a sympathetic ear in the US. And they say that France's determination to join the defense of West Germany - plus the added uncertainty about when the French might escalate from conventional to nuclear war - would likely deter a Soviet attack.

Parallel with the French-German partnership, Bonn hopes to make its current leadership of the EC more active - in part because the next two presidencies will rotate to the new and economically weak members of Spain and Greece, which cannot exercise strong leadership.

While granting Bonn's good intentions, some Italian officials are said by West German sources to have expressed skepticism that the West Germans can keep to their goals in the French-German partnership. The Italians fear that Bonn will be unable to prevent France from creating a ``Europe of variable speed'' in which France plays various partners differently, to the parochial advantage of Paris.