Service à la française is the practice of serving all the dishes of a meal at the same moment.
This style prevailed in the courts of French royalty, for it made the greatest impression for all the delicacies of the kitchen to emerge simultaneously. However, unless the kitchen and staff are enormous in relation to the number of persons being served, it is impossible for all dishes to be perfectly hot and ready to consume. Furthermore, it is impossible for the diners to consume each dish when it is at its peak. Thus modern fine-dining restaurants provide the dishes sequentially, so that they may be enjoyed individually: a style called Service à la russe.
A modified form of service à la française in which several large dishes are brought out for each diner to help themselves from is known as "family-style" in less formal restaurants. In the mediterranean, it is common to eat "tapas" or "meze" -style, where several small dishes are presented for the diners to share.
--- hertzmann below---http://www.hertzmann.com/articles/2004/service/
Service à la française evolved over time from the method of service used in the Middle Ages by royalty and the nobility. During that period, the only cutlery supplied the diner was a spoon. All the guests, at least each male guest, would bring his own knife, actually a dagger. Female guests would be served by men sitting nearby.
The various courses were brought to the diners in large bowls or platters which served two or more guests. Everybody was not served the same food. What each diner was served, as well as where each guest sat, was a function of his or her relative station in life. The choicer morsels, the rarer ingredients, and the better quality serving bowls went to those diners higher up the pecking order.
The typical formal dinner in the 19th century, whether enjoyed by the rich or the growing middle class, and whether served in a home or eaten in a restaurant, consisted of three courses, sometimes described as premier service, second service, and troisième service. Up until the 18th century it was still common, as in the Middle Ages, for sweets to be served as part of all three courses, but by the 19th century, the third course was closer to the modern concept of dessert.
The first course would commence with one or more soups. When these were removed, a couple of large plates of roasted or stewed meats, poultry, or fish, called relevés, were presented. These were accompanied by a series of entrées — smaller dishes of meat, poultry, or seafood — plus some entremets, small sweet or savory preparations. (In the Middle Ages, an entremet was entertainment presented between the mets, French for items “placed” before the diner. By the 18th century, these sweet and/or lighter dishes were now intended to provide a break between the larger heavier dishes of the course.) For larger meals, hors d’œuvres were place around the main dishes. Hors d’œuvres, literally “outside (the) work,” were not served before the meal as they are today, but around the main body of the meal.
The second course had the largest dishes of the meal, accompanied by vegetables, salads, and more sweet and savory entremets. By the 19th century, this course would contain the pièce de résistance, the center of the meal. The term apparently comes from the concept that diners had to resist eating too much of the first course in order to save room for this main dish. Also, this was not just a simple roast placed on a platter but an entire architectural construction of a combination of meats or seafood with a multitude of garnishes.
The third and final course was closest to the modern concept of dessert consisting of cheeses, pastries, and fruit. It could also include meat pâtés and other savory preparations. In the 18th century, this course bore more similarity to the earlier courses in that it would be centered on savory dishes with some sweet ones interspersed. The French word dessert evolved from desservir, meaning to “to remove what has been served, to clear (the table).” Also, much like today, the third service was prepared not in the kitchen but in the office, or pastry kitchen.
As the number of diners, and thus the number of dishes, grows, the likelihood of each diner being able to taste every dish diminishes. Table etiquette at the time dictated that any diner could ask for any dish to be passed to him or her. After the diner sampled from the dish, it would be returned to its original position on the table. It is not clear whether the diners ever actually passed the dishes to each other, or whether the act was carried out by what today would be referred to as waiters, but in those days they could be the host’s servants or the diner’s footmen. Etiquette dictated that while it was acceptable to obtain one or two dishes that were outside a diner’s reach, the diner should also not make a nuisance filling his plate with morsels that required excessive passing of plates.
By the mid-19th century, service à la française was becoming too burdensome, both in substance and fashion, for everyday dining. As early as the 1830s, Russian Prince Kourakin introduced to Paris society a method of service from his homeland, which the French dubbed service à la russe.
The main difference between service à la russe and service à la française is a matter of time and space. In service à la française, the dishes, at least in each course, are arranged spatially but presented to guests all at once. In service à la russe, the dishes are arranged temporally, i.e., served in succession, one after another. Plus the dishes are all offered to the guests by waiters, not passed by the guests. Instead of offering each guest a different assortment of dishes, everyone now is offered the same dishes throughout the meal. Also, with service à la russe, roasts are carved in the kitchen or on a sideboard, making it easier for the guests to select the portion they desire. And the food arrives at the table still warm, a problem for service à la française due to the elaborateness of its preparations.
By the last decade of the 19th century in France, service à la française is a memory and service à la russe has become de rigueur.