La France est une nation l�g�re - ce lieu commun antique est abondamment repris tout au long du XVIIIe si�cle, t�moignant de profonds bouleversements axiologiques, scientifiques et �thiques, dont ce volume collectif cherche � mesurer l'importance et les enjeux, en racontant l'histoire d'un autre si�cle des Lumi�res: celle d'un si�cle de la L�g�ret�. Propre aux repr�sentations que le XVIIIe si�cle fran�ais construit de lui-m�me, tant par rapport aux si�cles qui l'ont pr�c�d� que dans une logique de parall�le entre les nations europ�ennes, la l�g�ret� du XVIIIe si�cle est un important paradigme de l'historiographie qui s'est constitu�e sit�t apr�s la R�volution. Les h�ritiers du XVIIIe si�cle ne reconnaissent pas seulement en lui l'�ge de la raison et du progr�s, des Lumi�res et des droits du citoyen, mais �prouvent aussi tant�t du m�pris, tant�t de la nostalgie pour la pr�tendue l�g�ret� de ses moeurs, la futilit� de ses go�ts ou la frivolit� de ses enfantillages. Entre la bourgeoisie industrieuse du XIXe si�cle tirant profit des repr�sentations voluptueuses des f�tes galantes et l'int�r�t de notre �poque c�l�brant l'aimable frivolit� du si�cle de Marie-Antoinette, le XVIIIe si�cle en sa l�g�ret� n'a jamais cess� de s�duire certes, mais aussi de questionner le r�cit progressiste de la raison et de l'utilit� dans la d�finition des valeurs qui fondent notre communaut�. Aussi importe-t-il d'interroger les conceptions et les valeurs qui sont associ�es � la notion de l�g�ret� au XVIIIe si�cle, de mani�re � mieux comprendre dans quelle mesure elle a pu �tre associ�e � la fois au caract�re de la nation fran�aise en g�n�ral et au XVIIIe si�cle en particulier.
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The age-old clich� that France is a light-hearted nation is echoed repeatedly throughout the eighteenth century and bears witness to the deep axiological, scientific and ethical upheavals which this volume explores. By analysing the importance of, and issues at stake in, these transformations, the articles gathered here tell the story of another age of Enlightenment: the story of an age of lightness. Lightness is at the crux of how the French eighteenth century represents itself both in contrast with previous centuries and through parallels between European nations. The concept of lightness therefore constitutes an essential paradigm of the historiography that developed immediately after the French Revolution. The intellectual heirs of the eighteenth century do not only find in this period an age of reason, progress, Enlightenment and citizens' rights; they also feel, at times, contempt, at other times, nostalgia for the alleged lightness of its mores, the futility of its taste or the frivolity of its childish ways. Between the industrious bourgeoisie of the 19th century exploiting the voluptuous representations of f�tes galantes and the fascination of our own 21st century for the delightful frivolity of Marie-Antoinette's era, the 18th century in its lightness has never lost its charm. Yet, crucially, it also challenges the progressive narrative of the history of reason and usefulness in the definition of the very values on which our community is built. It is therefore essential to analyse the concepts and values associated to the notion of lightness in the 18th century. Such an approach yields breakthroughs in understanding why, and to what extent, this idea of lightness has been related to the French national character in general as well as, more particularly, to its 18th century.