National traditions and variants
Berets came to be popularized across Europe and other parts of the world as typical Basque headgear, as reflected in their name in several languages (e.g. béret basque in French, Baskenmütze in German, Basco in Italian or Baskeri in Finnish). They are very popular and common in the Basque Country. The colors adopted for folk costumes varied by region, red in Gipuzkoa, white in Álava, blue in Biscay, but eventually the Basques settled on blue berets and the people of Navarre adopted red berets while the black beret became the common headgear of workers in France and Spain. A commemorative beret is the usual trophy in sport or bertso competitions, including Basque rural sports or the Basque portions of the Tour de France.
Popularized by athletes, politicians, military and artists; to name but a few. The common worker’s headgear, also branches over into haute couture.
The beret fits snugly around the head, and can be “shaped” in a variety of ways – in the Americas it is commonly worn pushed to one side. In Central and South America, local custom usually prescribes the manner of wearing the beret; there is no universal rule and older gentlemen usually wear it squared on the head, jutting forward. It can be worn by both men and women.
Military uniform berets feature a headband or sweatband attached to the wool, made either from leather, silk, or cotton ribbon, sometimes with a drawstring allowing the wearer to tighten the hat. The drawstrings are, according to custom, either tied and cut off/tucked in or else left to dangle. The beret is often adorned with a cap badge, either in cloth or metal. Some berets have a piece of buckram or other stiffener in the position where the badge is intended to be worn.
Berets are not usually lined, but many are partially lined with silk or satin. In military berets, the headband is worn on the outside; military berets often have external sweatbands of leather, pleather or ribbon. The traditional beret (also worn by selected military units, such as the Belgian Chasseurs Ardennais or the French Chasseurs Alpins), usually has the “sweatband” folded inwardly. In such a case, these berets have only an additional inch or so of the same woolen material designed to be folded inwardly.
New beret styles, fully lined and made of “Polar fleece”, have become popular. These are unique in that they are machine washable.
The information above, courtesy of wikipedia.org