Paris — Poitiers is a provincial town in southwestern France, miles from the nearest port. Its customs post has only eight staff members.
Yet from now on, the French government has ordered that all imported videocassette recorders must pass through customs at Poitiers.
The new rule, which experts say will delay imports for weeks and could add 10 percent to the price of a recorder, is just one of a series of protectionist measures France has recently imposed.
The object, French Foreign Trade Ministry officials say, is to curb France's swelling trade deficit, which will probably reach 100 billion francs ($14 billion) this year, double that of last year.
The officials said that the measures represent retaliation for import restrictions its trading partners have already enacted. They are preparing reports on restrictions in other European countries and on ''the neo-protectionist American arsenal.'' But the European Community's governing Commission has opened legal proceedings against France for breaking free-trading rules.
Still, American diplomats here are worried that France's toughening trade attitude may be a sign of a more protectionist Europe in the future. More immediately, the Americans are worried that France may succeed in turning the GATT (General Agreement on Tariffs and Trade) talks in Geneva next week into a referendum on American economic policies.
''We maintain protectionism is threatening the world economy, and want a strong declaration to come out of GATT stressing these dangers and pledging to work for further liberalization of trade,'' a high-ranking American diplomat here said. ''The French want the communique to blame American monetary and fiscal policies for the trade strains. If they succeed, they would eviscerate GATT's work program for the 1980s.''
The French don't hide their pique with GATT or the United States. French Foreign Trade Minister Michel Jobert said recently that he ''doesn't see any interest'' in the coming GATT meeting, explaining that it is ''outdated before it starts because all that will be talked about is the philosophy and trade of our grandfathers.''
The dollar's increased strength against the franc this year - the franc is now at 7.3 to the dollar vs. 5.66 at the beginning of the year - is also angering the French. The strong dollar has caused France's bill for oil, almost all of it imported and priced in dollars, to soar by 12 billion francs ($170 million) this year.
''The Americans must realize that they have to be more responsible with their currency,'' the Foreign Trade Ministry official said.
But even the Socialists admit that France's trade problems are not merely a result of the strong dollar. During their first year in power, economists say, increased government spending spurred an import boom. At the same time, according to the economists, France's large third-world markets have weakened.
''Our deficit has become terrible,'' the Trade Ministry official said. ''The country cannot support it any longer.''
Particularly worrisome, trade officials say, has been the boom in sales of imported consumer-electronic products, mainly from Japan. Videocassettes alone - 75 percent of which come from Japan, though France hopes to produce a million annually by 1986 - have cost France 1.5 billion francs this year.
Against this background, the government acted earlier this month. In addition to the Poitiers regulation, customs papers for all imports must now be written in French; goods will have to state their country of origin; foreign-exchange accounts of nationalized industries are to be controlled; and exports of patents will be closely guarded. Bilateral trade negotiations are also to be started, with yet unspecified countries to balance the imports and exports.
''There will be more measures, too,'' a Trade Ministry official warned.
But the official added that as a country dependent on trade for its livelihood and as a member of the Common Market, which has abolished intra-European tariffs, France is limited in the measures it can take unilaterally.
Still, France could construct a thicker jungle of administrative and technical obstructions. And the French can try to persuade their European partners to take a tougher trade stance.
Already, they are urging the Common Market to get tough on Japan. Last month Mr. Jobert demanded that the European Commission negotiate voluntary trade restraint agreements with Japan. He suggested that France would take unilateral action if the Commission did not act.
''We would prefer that the Community act together,'' Mr. Jobert said. ''But we do not have the intention of waiting too long a time.''
So far the Commission has responded only by opening legal proceedings against France for breaching free-trading rules with its ''Poitiers'' regulation and its requirement that customs documents be written in French. But few expect the French to back down.
''They are just warming up,'' the American diplomat said. ''Their recent actions are just signals that they are ready to play tough.''