The standards that the Académie imposed on French drama were derived from the writings...
Tartuffe, or The Impostor, or The Hypocrite, was written by Molière in 1664, at a time when the Académie française was actively involved in regulating French language, grammar, and literature, including French drama.
The standards that the Académie imposed on French drama were derived from the writings of the French neoclassicists, who based their principles of drama on the plays of Aeschylus, Sophocles, Euripides, and other ancient Greek playwrights from the 5th century BCE, and on Aristotle's Poetics, written around 355 BCE.
The French neoclassicists interpreted Poetics as Aristotle's rules for Greek drama, rather than simply Aristotle's observations and analysis of plays that were written a hundred years before Aristotle wrote Poetics.
The Académie decreed that French plays must conform to the "three unities" of action (a single, unified plot, and no subplots), of time (the action of the play must occur within a single day), and of place (that the play occurs in a single location).
French plays of the period were also required to conform to standards of language and composition. Plays must be composed exclusively of alexandrine couplets, which are rhymed couplets (two lines) written in iambic hexameter—twelve syllables per line, in an iambic rhythm pattern (da-DUM).
da-DUM da-DUM da-DUM da-DUM da-DUM da-DUM
Additionally, each line must contain a caesura, or a pause, between the 6th and 7th syllable of each line.
da-DUM da-DUM da-DUM [pause] da-DUM da-DUM da-DUM
The couplet could be split between two characters, but each line still had to conform to the "rules" of dramatic construction.
One further requirement is that the two lines of the couplet must form a complete thought.
These are the first two lines of Tartuffe, in the original French:
Allons, Flipote, allons; que d'eux je me délivre.
Al-LONS, Fli-POTE, al-LONS; [caesura] que D'EUX je ME dé-LIVRE.
Vous marchez d'un tel pas, qu'on a peine à vous suivre.
Vous MAR-chez D'UN tel PAS, [caesura] qu'on A peine À vous SUIVRE.
There have been no successful translations of Tartuffe into English verse that maintain the iambic hexameter of the original play. Most translations of Tartuffe into English verse are done in iambic pentameter (ten syllables per line), such as the translation of these same two lines by Richard Wilbur:
Come, come, Flipote; it’s time I left this place.
Come COME Fli-POTE; [caesura] it's TIME I LEFT this PLACE.
I can’t keep up, you walk at such a pace.
I CAN'T keep UP, [caesura] you WALK at SUCH a PACE.