Historically, regions of the world have made fermented beverages with the ingredients on hand. In Germany, eastern Europe and the Low Countries (now Belgium, the Netherlands, etc.), this was grain and hops; in England and Scandinavia, honey and spices; and in France and Italy, grapes. The beverages of the ruling classes were made with ingredients that produced the best, most complex flavors. Thus, in Germany, we see beers made with wheat being reserved by law for the nobility, while the peasantry got beer made from barley. In England, the nobility drank mead (honey wine) until the grape was imported from France, at which point, mead largely became obsolete. In much of France, however, the soil and climate are perfect for the growing of grapes, not for barley. Thus, with the exception of the regions of Nord/Pas-de-Calais, and Alsace-Lorraine, which border Belgium and Germany, beer was not widely made, but wine was. Also, note that there was constant competition for grains between beer brewing and bread baking. If it was easier to secure grapes for the making of alcoholic beverages, then the grain could be reserved for the making of bread. The last piece of this puzzle is that Stout and Porter originated in England. Referring again to the historical record, in early medieval England, the drink of the choice was mead (the word ale was derived from wassail, itself a derrivative of the Old English "Wachts hale," meaning "Be healthy," said when drinking mead; spiced mead was the original ale). When barley and hops became available, the peasantry turned to beer. In the early 1700s, with the price of barley on the rise, brewers began roasting their malts more in order to give the beer more flavor with less barley. These dark, rich beers became popular with porters in London, and so came to be known as porter beer, or simply porter. The original name for what we now simply call stout was "stout porter," so the two belong to the same style. A stout is distinct from a porter in that stout contains roasted, unmalted barley and porter does not. Stout was originally brewed by Guinness, a brewer of porters since 1759, in Dublin in 1820. So, with wine, rather than beer being the common drink in France, and porter and stout being relatively contemporary (in terms of the importation of beverage styles from country to country), English beer styles, it is hardly surprising that porter and stout would be scarce in France. French beers take their cues from the regions more accessible to France. The beers of Nord/Pas-de-Calais are reminiscent of Belgian ales. Those of Alsace/Lorraine are much like German beers. Also, French beers are somewhat reminiscent of wine, in terms of complexity and and body. This may be due to the yeast strains used, which vary from region to region. Pleass note that dates and regional info in this answer came from http://en.wikipedia.org/wiki/Stout http://en.wikipedia.org/wiki/Porter_%28beer%29 http://www.frenchbeer.info/France/france.html Other info came from Lt. Col. Robert Gayre and Charlie Papazian, "Brewing Mead/Wassail: in Mazers of Mead." Boulder, Colorado: Brewer's Publications, 1986. and out of my hot little head.

The last answer is very good and I do not disagree with one word of it. But to illustrate further the point that was made about beers "originating" somewhere there is a real life example happening in France right now, which is directly relevant ot the question. The microbrewers of Brittany have started making a beer from the sort of dark buckwheat (or blé noire) that is used by Breton crêpereries make the dark savoury pancakes called galettes. The end product tastes about half way between a wheat beer and a porter or stout (depending on exactly which brand). These beers are quite striking and are clearly taking off with local beer drinkers.