The word "chevalier" originally means "knight," that is, horse-riding warrior (from Latin caballus, horse). It came to take a number of different meanings that are easily confused.
Originally, knighthood was an induction into a body of professional soldiers, trained in specialized combat and bound by certain rules of conduct. THe first stage of apprenticeship led to the status of "ecuyer" or esquire, after which one could become a knight after a particular ceremony, whose details varied.
By the time knights ceased to be an effective part of warfare in the 16th c., the ceremony had ceased to be practiced, and the term had become honorary. What exactly it meant, and who could use it, is a little unclear. An ordonnance of 1629 prohibited anyone from using the style of knight "who have not received it from our predecessors or ourselves, or who do not deserve it by the eminence of their quality" ("deffendons à tous non-Nobles d'en prendre la qualité, de se dire Escuyers, ny porter Armoiries timbrées; & à toutes personnes de prendre la qualité de Chevalier, s'ils ne l'ont obtenuë de nos predecesseurs ou de Nous, ou que l'eminence de leur qualité ne la leur attribuë"). In the mid-18th century, Diderot's Encyclopédie defined the term as "signifie proprement une personne élevée ou par dignité ou par attribution au-dessus du rang de gentilhomme" (s.v. chevalier), and lists as first privilege of the nobility "à pouvoir prendre la qualité d'écuyer ou de chevalier, selon que leur noblesse est plus ou moins qualifiée, & à communiquer les mêmes qualités & les privileges qui y sont attachés à leurs femmes quoique roturieres, & à leurs enfans & autres descendans mâles & femelles" (s.v. noblesse). It also defines "noblesse de chevalerie"as "celle qui provient de la qualité de chevalier, attribuée à quelqu'un ou à ses ancêtres, en lui donnant l'accolade" (s.v. noblesse de chevalerie).
Jurists differed on whether the style was hereditary. La Roque ( Traité de la Noblesse, 1678; p. 344) thought not: "c'est un abus que de faire deux degrés de Noblesse, l'un de Chevalier, l'autre d'Ecuyer: et la Chevalerie ne vient point de la naissance, mais dépend absolument de la grace du Prince." For him, the title was ad personam and could only be granted by the king, either by ceremony or through the grant of "lettres de chevalerie", for which Lar Roque provides examples from 1315.
Chevalier was also a title attached to members of the orders of knighthood: these were, of course, purely ad personam. Note, however, that by an edict of 1750, three consecutive generations of officers who were recipients of the order of Saint-Louis and who met certain requirements on duration of service endowed the issue of the 3d member with hereditary nobility (but not knighthood; see more details). This feature was recalled in an ordonnance of 1814 discussed below.
No French order of knighthood conferred nobility per se, so these knights were not noble.
Louis XIV gained parts of Flanders in 1668 and Franche-Comté in 1678; he continued the practice of issuing lettres de chevalerie (although La Roque (Traité de la Noblesse, 1734, p. 69) cites (French?) examples from 1315 to 1605). Bouly de Lesdain, in Intermédiaire des Chercheurs et des Curieux, Nov. 1965, col. 1043, cites creations by Louis XIV in 1660 in Artois, 1669-71 in French Flanders and Hainault. More importantly, in November 1702, at the onset of the War of Spanish Succession, Louis XIV promulgated an edict creating 200 hereditary titles of chevalier, which could be obtained for a fee by any untitled member of the nobility of Flanders, Artois, and Hainault. The title was transmissible to all male descendants of the grantee. Not all letters had been sold by 1789. See the text of one such letter below.
These titles are highly unusual, in part because of their explicit geographical limitation. They are also a departure from the normal forms for titles in pre-1789 France, because the title didn't seem to be attached to land: no fiefs were raised to a "chevalerie". That is not the only such departure, as the king had started granting purely nominal hereditary titles (such as marquis).
That the family became part of the French nobility is without doubt. They appear in Jougla de Morenas, Woëlmont de Brumagne and even Saint-Simon and Séréville, even though they are extinct since 1872 according to Woëlmont de Brumagne. Four members of the family showed up when the nobility of Flanders was called to elect its representatives for the Estates General of 1789. Two of them (Pierre-Ernest-Joseph, seigneur de Noyelles and Charles-Louis-Philippe, seigneur de Douay) are styled "chevalier" in the rolls (La Roque & Barthélémy: Liste des Gentilhommes ...). The other two, as it happens, were elected representative and deputy-representative: Louis-Séraphin du Chambge, baron de Noyelles (1732-94) who resigned in December 1789 because of his dislike of the Revolution, and his replacement Pierre-Joseph du Chambge, seigneur d'Elbecq (1733-93), an army officer who was a strong supporter of the Revolution (he resumed active service in 1792 and was sent to the Pyrenees front where he died of natural death).
The Liessart branch, settled in Lille, continued to use the title of chevalier, and the death certificate of one of them, dated 1825, also uses the title. The problem that the letters patent of 1673 were not explicit about the mode of transmission. So, in 1852, when they tried to change the spelling of their name from Duchambge to Du Chambge de Liessart and insert the title of "chevalier" in the Etat civil, they failed in the civil courts (they did get the spelling change). Hence their recourse to the Conseil du sceau, who confirmed their hereditary title of chevalier by decree of 25 Jun 1860 (case reported in Recueil Sirey 1852, part 2, p. 102).
There are other examples of surviving hereditary titles of chevalier. Perusing Woëlmont de Brumagne's volumes on La noblesse subsistante, one finds a grant of lettres de chevalerie to the family de Perrey in Franche-Comté, in 1720. The other examples are all from Artois, Flanders and Hainaut, which can be checked in Séréville and Saint-Simon (those missing in the latter are marked "extinct?"):
In all, the king granted 104 new titles of chevalier to members of the Legion of Honor, 4 to members of the order of Saint-Louis, and 5 titles to 2d generation members of the Legion of Honor. He also granted 144 titles to members of the Legion of Honor who had already received the title under Napoleon, at their request.
Under the July monarchy (1830-48), the minimum income requirements became
moot; no further grants of 1st-generation chevaliers were made in France
after 1830. A total of 5 2d-generation confirmations were made.
Under the Second Empire (1852-70) 24 confirmations were made, variously
under the Napoleonic statutes or under the ordonnance of 1814. One
unique case is that of Chambge de Liessart, discussed
above. After 1870, only two confirmations have been made, including
the only known case of a 3d generation confirmation under the statute of
1814 (Flury-Hérard, granted 30 Jan 1811, confrimed 25 Nov 1814,
23 May 1866, 25 Sept. 1874): this would be the only fully hereditary title
of chevalier surviving in France, at least under the post-1808 statutes.
LOUIS...
Nous avons toujours à l'exemple des rois nos prédécesseurs jugé convenable au bien de l'Etat et à la gloire de notre règne, d'accorder des distinctions particulières à ceux de notre noblesse qui se trouvent les mériter, tant par l'ancienneté de leur origine que par leurs services et ceux de leurs ancêtres, et pour cet effet de leur départir des titres d'honneur, qui, passant à leur postérité, pussent perpétuer leur affection pour notre personne et notre état à cette noble émulation qui conduit à former de grands hommes, tant dans la robe que dans l'épée, et voulant donner à Sieur G... escuier, sieur de Couchy et autres lieux, noble d'extraction ; issu de l'ancienne et noble famille du nom de Grenet, originaire de notre Province d'Artois, établie depuis plusieurs années ès pays de Flandres et Cambrésis, et à ses descendants nés et à naître en légitime mariage, des marques de la satisfaction et récompense des services qu'il nous a rendus à l'exemple de ses père et ayeuls... (rappel des services rendus)... nous avons estimé que nous ne pouvons rien faire qui soit plus digne de notre grandeur et de notre authorité, et plus conforme à nos désirs et au bien de notre Etat, que de décorer ledit sieur G... et ses descendants mâles du titre de CHEVALIER.
A ces causes, voulant donner audit sieur G... des marques de notre bienveillance et de l'estime particulière que nous faisons de sa personne par un titre qui l'oblige de plus en plus, ainsy que sa postérité, à notre service et à celui de notre Etat, Nous, de notre grâce spéciale, pleine puissance et authorité royale, avons par ces présentes signées de notre main, fait et créé, faisons et créons ledit G... chevalier, ses enfants et descendants mâles nés et à naître en légitime mariage, pour dudit titre de CHEVALIER, droits, honneurs, privilèges prérogatives et prééminences y appartenans, jouir pleinement et paisiblement et à toujours tant en fait de guerre ès armées et assemblées qu'en jugement et hors de jugement et partout ailleurs où besoin sera, tout ainsy qu'en jouissent les autres chevaliers dans toute l'étendue de notre royaume, pays, terres et seigneuries de notre obéissance. Si donnons en mandemant à nos amés et féaux conseillers, les gens tenant notre cour de Parlement de Flandres à Douay, Conseil provincial d'Artois et autres nos officiers et justiciers qu'il appartiendra, que ces présentes ils aient à faire registrer, et de tout le contenu en icelles faire jouir et user ledit Sieur G... et ses enfants et descendants masles nés et à naître en légitime mariage, Pleinement, paisiblement et perpétuellement, cessant et faisant cesser tous troubles et empêchements, nonobstant tous règlements, dispositions et autres choses à ce contraires, car tel est notre plaisir. Et afin que ce soit chose ferme et stable à toujours, nous avons fait mettre notre scel à des présentes.
Donné à Versailles...
According to Texier, there are still potential hereditary knights: descendants of the grantees of 1702, members of the L of H who received letters patent and were succeeded by 2 generations of members of the L of H (he cites the example of the Vignon family), and descendants of the 116 grantees of hereditary titles between 1809 and 1810.