I would like to thank you in finding the definition for “colonne par regiment”...it was all I needed to fill in the blanks.

You see...Lapene was correct up until the execution of a passage of lines...then Maransin informs Lapene of the preceding execution made by the 2nd division.

Both divisions were originally formed en colonne par regiment...while they were manouvring...

Then Girard’s division...once it was within range...marched in attack columns...with each regiment being an attack column....but the battalions were not in colonne d’attaque...

Since you are well versed in the ligne de science...remember that according to the French Military System (doctrine)..the colonne d’attaque was a column for action, unlike the colonne par division...we then find in the Instructions of 1809; that the colonne par division en masse replaced the colonne d’attaque, thus making it a column of action as well.

We also know that the colonne d’action was used with great success in the 1806 campaign...but dropped out of use in grand bodies of troops shortly afterward. Of course when the Federalists in America tried to gain control of the militia in order to suppress the political opposition to the Constitution of 1787. They formed their own militia companies using the colonne d’attaque as l’ordre hubituel in 1813...which is both surprising and quite interesting...

So Girards division advanced en serre en masse par regiment

One brigade formed on the left....one brigade formed on the right...all regiments formed in approaching columns.

40eme--34eme----------xxeme--xxeme
40eme--34eme----------xxeme--xxeme

Then as Gerard arrived near the enemy positions...the approaching columns (regiments) became attacking columns...or colonne d’attaque

When the second division was given orders to prepare for a passage of lines...the battalions were already formed en colonne par regiment...the battalions opens up en colonne distance entiere...(if not already) and each platoon executes un movement de conversion...(right out the reglement)...and you then have the entire regiment en ligne...and then each battalion in the line ploys to colonne d’attaque...the battalions then wheeled into line and each battalion formed a colonne d’attaque...

Jomini describes the term ...en colonnes d'attaque par bataillon...as a battalion formed en colonne d’attaque

He makes it perfectly clear that he believes that if the French had formed their battalions in colonne d’attaque at Talavera, Bussaco, Fuente de Onor, Albuera (leading division), and at Waterloo that perhaps the conclusion would not have ended as it did.
"Arrivé au point d'attaque, le 5me corps change de direction par un mouvement de tete de colonne à droite; la Division Girard marche à l'ennemi en colonnes d'attaque. La 2me Division derierre, é 150 pas de distance, en colonnes d'attaque par bataillon."

Military Theory and the Line of Science is quite fascinating (-at least for myself)... there is so much to learn in these matters...so I do hope that we shall be able find ourselves discussing other issues in the future.

Respectfully Et Best Regards,
Art