“There is but one way to bring about the triumph of liberty, of justice, and of peace in Europe's international relations, to make civil war impossible between the different peoples who make up the European family; and that is the formation of the United States of Europe.”

Océan - Tas de pierres (1942)

Source: How Europe Underdeveloped Africa (1972), p. 53.

Source: Books, Beyond Order (2021), p. 191

Attributed to Washington in "Farewell to the United States of Europe: long live the EU!" by André Fontaine at Open Democracy (29 November 2001) http://www.opendemocracy.net/democracy-europefuture/article_344.jsp. It appears to have originally circulated in French:
:: Je suis citoyen de la Grande République de l'Humanité. Je vois le genre humain uni comme une grande famille par des liens fraternels. Nous avons jeté une semence de liberté et d'union qui germera peu à peu dans toute la Terre. Un jour, sur le modèle des Etats-Unis d'Amérique, se constitueront les États-Unis d'Europe. Les États-Unis seront le législateur de toutes les nationalités.
: An anonymous blogger in "Did George Washington predict a "United States of Europe"? (30 January 2010) http://racehist.blogspot.com/2010/01/did-george-washington-predict-united.html showed that it derived from Gustave Rodrigues, Le peuple de l'action: essai sur l'idéalisme américain (A. Colin, 1917), p. 207:
:: Washington écrivait à La Fayette qu'il se condérait comme « citoyen de la grande république de l'humanité » et ajoutait : « Je vois le genre humain uni comme une grande famille par des liens fraternels ». Ailleurs il écrivait, prophétiquement: « Nous avons jeté une semence de liberté et d'union qui germera peu à peu dans toute la terre. Un jour, sur le modèle des Etats-Unis d'Amérique, se constitueront les États-Unis d'Europe. »
: A translation by Louise Seymour Houghton ( The People of Action: An Essay on American Idealism (1918) http://books.google.com/books?id=b8Y9AAAAYAAJ) reads:
:: Washington wrote to Lafayette that he considered himself a "citizen of the great republic of humanity," adding: "I see the human race a great family, united by fraternal bonds." Elsewhere he wrote prophetically: "We have sown a seed of liberty and union that will gradually germinate throughout the earth. Some day, on the model of the United States of America, will be constituted the United States of Europe." [pp. 209-210]
: The first two quotations come from a letter to the Marquis de Lafayette of 15 August 1786 (see above) as quoted in Joseph Fabre's Washington, libérateur de l'Amérique: suivi de Washington et la revolution Américaine (Ch. Delagrave, 1886), and the third is also found in that source where, although placed between quotation marks, it is clearly intended as the author's own comments on what "Washington and his friends" were saying to the world by establishing the American Constitution. Gustave Rodrigues mistakenly printed Fabre's words as Washington's alongside some actual observations of his from a letter to Lafayette, and so created the misquotation.
Misattributed

The Unity of India (1948)

"In the Storm" in Le Socialiste http://www.marxists.org/archive/luxemburg/1904/05/01.htm as translated by Mitch Abidor (1 - 8 May 1904)
Context: The Russo-Japanese War now gives to all an awareness that even war and peace in Europe – its destiny – isn’t decided between the four walls of the European concert, but outside it, in the gigantic maelstrom of world and colonial politics.
And its in this that the real meaning of the current war resides for social-democracy, even if we set aside its immediate effect: the collapse of Russian absolutism. This war brings the gaze of the international proletariat back to the great political and economic connectedness of the world, and violently dissipates in our ranks the particularism, the pettiness of ideas that form in any period of political calm.
The war completely rends all the veils which the bourgeois world – this world of economic, political and social fetishism – constantly wraps us in.
The war destroys the appearance which leads us to believe in peaceful social evolution; in the omnipotence and the untouchability of bourgeois legality; in national exclusivism; in the stability of political conditions; in the conscious direction of politics by these “statesmen” or parties; in the significance capable of shaking up the world of the squabbles in bourgeois parliaments; in parliamentarism as the so-called center of social existence.
War unleashes – at the same time as the reactionary forces of the capitalist world – the generating forces of social revolution which ferment in its depths.

Chap. 17 : The Curious History of Europe
On History (1997)

1860s, Speech to Germans at Cincinnati, Ohio (1861), Commercial version