Full spoilers follow. Because the film is history, its destination is known; the interest lies in how Baudry organises it. This second part picks up the Free French in Libya, moves through the North African campaign, crosses to the Landings, and terminates with the Liberation of Paris.
The structural key is the promotion of Philippe Leclerc (Niels Schneider) to something near co-lead. The film explicitly builds him as de Gaulle's double: the same intransigence, the same taste for disobedience, deployed at the level of the battlefield rather than the negotiating table. That doubling is what allows the narrative to stay continuous across a chaotic period — the through-line from the desert to the capital is not a strategy but a man and his armoured division.
The climax is the arrival of Leclerc's armoured division at the liberation of Paris. Read plainly, it is the reward: the exile returns, the capital is French again, the diptych closes. Read against everything preceding it, it is also the settling of the political argument that has occupied de Gaulle since the first film — by having French troops under French command take the city, the Free French claim to legitimacy stops being a rhetorical assertion and becomes an accomplished fact. The whole two-film structure exists to make that entry mean something more than a military event.
The title supplies the final gloss. Éluard's Liberté ends every stanza with 'j'écris ton nom' — the name written on notebooks, on sand, on ruins, always in advance of the thing itself. The film's retrospective revelation is that this is what the two films have been describing all along: not a war won but a word insisted upon until reality was forced to match it. What looks in the first part like futile obstinacy is revealed in the second as a long act of writing.