Hairstyles this year are sleeker, smoother, more sophisticated

There are over 3,000 coiffeur salons in Paris. They range from little obscure ones to big important ones headed by the undisputed master, Alexandre, who has coiffed more crowned heads and celebrities than any other hairdresser in the world. Many Frenchwomen with a limited amount of money to spend on their wardrobes would rather go to a first-class hairdresser who charges hair-raising prices and then stint a bit on the actual clothes.

Alexandre is practically as legendary as his famous international clientele, and after 45 years in business he's the veritable king. He also creates all the avant-garde styles for the mannequins presenting collections in the leading couture and ready-to-wear fashion houses. At the time of the showings the maestro and his team of 20 assistants hover over the tresses of more than 400 mannequins engaged each season to launch the new looks. Each designer has his individual approach relating to his clothes, and his taste may range from wild, wavy manes to sleek chignons that don't detract from the exotic millinery which is making such a big comeback for winter.

''Our job is to analyze the overall silhouettes the designer wishes to define and strike the right note for each one,'' says Alexandre.

Hairstyles vary with the vast scope of fashion itself, and trends definitely change from one season to the next to accentuate these various messages.

One must have confidence to cut, however, as it's obviously impossible to ''try on'' a new style, and the months that it takes for a mistake to grow out often make total hibernation seem wonderfully attractive.

These mistakes have been known to happen in some of the various training schools for future professionals working under the guidance and, one hopes, the watchful eye of skilled instructors. It's comparable to American ''barber colleges,'' and the pupils need all the hairy heads they can get to practice on. Though it may appear tempting to one and all, the completely free session at these experimental ''coiffeur'' classes has often ended in disaster for the ''guinea pig.''

The dominant trends for winter, '84-85? Generally it's a sleeker, smoother, and more sophisticated look after summer's shorter wild cuts and those natural affectations. The wonderfully attractive hats with a few sprinklings of pure goofiness were underscored by hairstyles that were generally played down in the haute couture collections.

What one currently sees on the streets of Paris is a different story. The punks and rockers have migrated from London's King's Road and are out en masse on the Left Bank, turning one of women's potentially greatest assets into less than a ''crowning glory.''