My english is not the best but i'll try to provide some elements ... because i've read atrocious things

So why would the french do that ?

2 reasons : - To administer & exploit its new possession.

Since the political situation in France was not very stable ( 2nd Republic, 2nd Empire, 3rd Republic... ) and french politicians were aware of that, the 1848 Constitution stated :

Art.109 : "Algeria has been declared a french territory - and will be ruled by decrees - until a special bill is voted in order to place it under the current Constitution."

This special bill has never been voted.

One of the main objective was to perpetuate the colonization process despite the political situation / troubles in the French Metropole. It was also an experiment on what was at the time the largest colony of France, "an administrative experiment" , which if sucessful, could have been imitated in all of the colonies. By exporting French legal system in Algeria, France could now fully exploit/control its territory and protect the huge population of French migrants who emigrated to Algeria ( and collect taxes ! ) : land spoliation was helped by decrees in favour of europeans, coercive mesures against natives, etc..

Now think of Algeria at the time as what we see today in Afghanistan. There was absolutely no "unity", Algeria was composed of hundreds of different Ethnic groups, some of them ennemies since the dawn of time. One could argue that France "created" Algeria, because the idea of Algeria as a nation emerged during the 50"s with the Jabhat at-Tahrīr al-Waţanī group... Anyway, those Tribal leaders would give the french a hard time , attacking the french convoys, controling some areas/villages, they would collect taxes, etc... By turning Algeria into a departement, France tried "to break-up" the tribe system, they would reorganize the territory and its population, turning the tribes into "douars. A douar was an " artificial " village created by the french, in which they would regroup people from different tribes/areas to bring them some " enlightenment" ( or freedom as our american friends would call it). On this matter , /u/DerProfessor explained very well the ideological differences between French/English in the colonization process.

Another reason to turn Algeria into a french territory was because of the fierce competition between the military power and the civilian authority at the time. Under Military governorship , the economy was a complete disaster ( big crisis in 1866-1870 ).

Military governorship was not working at all, that's when the Emperor decided to change the administration for a civilian authority - which proved to be much harsh towards natives- . Algeria was now composed of 3 "departements", under the rule of a "civilian governor", Algerian jews were declared french citizens ( because $$$ / jewish communautarism ), and the creation of a " special native code". So yeah, even though Algeria was technically part of France, its people were never treated as french citizens ( I will need to check but I think they only got the right to vote after WWII in 1947 ).

I will add further information later on the rise of imperialism at the time, the critics of colonialism in France , etc.... I'm late for work :)

Source : This is a very very very rough summary of a +200pages chapter in this book : " La France de 1848 à nos jours", M. Agulhon.

further reading : Tocqueville wanted Algeria to become for France what the americans colonies had become for England https://wikileaks.org/gifiles/attach/9/9388_1405738.pdf

I specialize in imperialism... however, I'm a bit weaker on French political history, so this will be a bit less detailed in terms of the personalities involved. But I think there are four different elements coming together here.

First, Algeria is one of the oldest substantial colonies. French colonial outposts in the New World go back to the 16th c. (fur trading outposts), and in Africa and India (French East India Company) to the 17th c. But the French invaded Algeria in 1830, after the infamous "fly-swatter" incident. (the Dey of Algiers whacked a French representative with his fly-swatter after being asked to repay loans: no choice but to invade!) Of course, the invasion was not about that incident--it was more to prop up the Orleanist regime (a new, 'bourgeois' monarchy) with a foreign adventure/victory. The problem was, it turned into a really rough war, and it took the French two decades to pacify Algeria. And revolts broke out again in the 1880s. This meant a HUGE commitment of French military resources over not just years, but over a century. Which means the various regimes (Orleanists, 2nd Republic, Napoleon III) all had to justify this expenditure of money and men, by insisting over and over that Algeria was "worth it."

Second (and this is most important) unlike colonial outposts in the Americas, Africa, India, or (eventually) Indochina, there were a huge number of European setters that poured into Algeria. Maybe 100,000 Europeans had moved there by 1848, and a bit fewer than half were French. They were largely all from the lower classes--mostly poor farmers--looking for economic opportunity (given a population boom back in Europe.) This huge setter-population is pretty unusual for this second phase (post-Americas, post-Australia) of European imperialism. Kenya, a British setter colony, had nothing like these numbers six decades later. So Algeria (for the French) was a bit more like the "13 colonies" of North America for the British, in terms of demographics, than like the other post-1880s imperial acquisitions (like British Kenya or German Southwest Africa). Remember that the American colonists "felt" English (right up until they were asked to pay taxes), and a similar situation emerged with the French-Algerians.

Third, Algeria became an official Department in 1848. The 1848 Revolution was key here: it formed the 2nd Republic. And, just as the first Republic (coming out the Revolution of 1789) had moral and ethical issues with the slavery of the French sugar colonies (notably Saint Domingue--Haiti), so too did the radical republicans of the short-lived 2nd Republic have issues with the status of (occupied) "colony" with Algeria. My specifics on the politicians here are hazy; did Lamartine or Blanc support it? I don't know--sorry! Someone help me out here? But certainly, the ideals of republican, representative government coming out of the 1848 revolution propelled the switch in status for the French-Algerians, who thereafter had "representation" in France.

Meanwhile, the French-Algerian colonists ("colons"), horribly exploiting the indigenous Algerians, had developed into a profoundly racist society. (This was not so different from what was happening with Boers in South Africa, or slave-holding society in the Southern US, although slave-holding was not widespread in Algeria.) So the exploitative, increasingly racist French-Algerian colons needed backing--and clung tightly to their status as "French", realizing correctly that it would allow them police and military backing from the "hexagon"--i.e. continental France--should their colonial subjects in Algeria get restless.

Finally, and most importantly, ideology: perhaps because of this emerging Algeria-as-part of-France thing, and partly prior to it, the French increasingly saw their "special" path among the European colonizers as remaking the world by exporting (French) civilization. (I'm thinking specifically of Alice Conklin's excellent book Mission to Civilize here.) The English were mere traders, seeking to make money; but the French empire had a nobler mission, namely to expand civilized, republican "Frenchness." Which is why the French devoted so much effort to getting French colonial subjects to speak French. This peculiar ideology of French imperialism was the standard 'civilizing-mission' argument on steroids: and it locked the French ever deeper into Algeria. Algeria's status as "oldest and closest" colony (though it wasn't the oldest by far) increasing made it seem as the model upon which the entire French imperial mission would be judged a Success or a Failure.

Which was why the Algerian war of the 1950s was so traumatic: many French were locked in to an uncompromising position by their ideology--we must not abandon our mission to civilize! nor abandon the French-Algerins!--which left them locked into an unwinnable war. And only a bona-fide War Hero like de Gaulle would have the stature to confront this ideology, and allow the French to even think about Algerian independence.

Hiya everyone!

I'm afraid that so far in this thread, there have been a large number of incorrect, speculative, or otherwise disallowed comments. A good half of them have been asking about the deleted comments, which merely compounds the issue. As such, they were removed by the mod-team. Before you attempt answer the question, keep in mind our rules concerning in-depth and comprehensive responses. Answers that do not meet the standards we ask for will be removed.

Additionally, it's rough on the OP to further derail this thread with off topic conversation, so if anyone has further questions or concerns, I'd appreciate them being directed to modmail, or a META thread.

Thank you!

Followup question, what was the role of Marseilles in the role of colonization and decolonization?