Based on the provided search results, here is a summary of the French colonization of Vietnam, Cambodia and Laos in the 1870s:
The French gradually extended their control over Vietnam, Cambodia and Laos over a period of more than 350 years, but their conquest accelerated in the 1870s[2][16].
In Vietnam, the French captured the city of Hanoi in 1873 to gain access to southern China and Vietnam’s coal and mineral supplies. They returned to fully conquer Hanoi in 1882[13]. The Vietnamese emperor was forced to sign a treaty in 1883 that turned northern Vietnam (Tonkin) and central Vietnam (Annam) into French protectorates[2][5].
In Cambodia, King Norodom requested a French protectorate in 1863 to protect against Vietnamese and Siamese threats. The French established control over Cambodia’s foreign affairs through an 1863 treaty[1][3][5]. In the late 1870s, French officials pressed for greater control over Cambodia’s internal affairs as well[3][15].
Laos came under French control later, between 1893-1907, as France sought to counter British influence in Siam and gain access to the Mekong River[5][9][11][17].
By 1887, France had consolidated Vietnam, Cambodia and Laos into the Indochinese Union, also known as French Indochina, though conquest was not fully complete until the 1890s[2][5][7]. The French aimed to exploit the region’s resources like rice, rubber, opium and access to Chinese markets[7][16]. However, French colonial policies largely benefited the French while depriving and exploiting the local populations[14].
In summary, the 1870s marked an important decade when France accelerated its conquest of Vietnam and Cambodia in particular, laying the groundwork for the formation of French Indochina. Laos was added later to complete France’s colonization of the region by the early 1900s.
Citations:
[1] https://factsanddetails.com/southeast-asia/Cambodia/sub5_2a/entry-2846.html
[2] https://en.wikipedia.org/wiki/French_conquest_of_Vietnam
[3] https://www.britannica.com/topic/history-of-Cambodia/Tai-and-Vietnamese-hegemony
[4] https://photius.com/countries/cambodia/national_security/cambodia_national_security_the_french_protector~43.html
[5] https://en.wikipedia.org/wiki/French_protectorate_of_Cambodia
[6] https://www.britannica.com/place/Vietnam/The-conquest-of-Vietnam-by-France
[7] https://en.wikipedia.org/wiki/French_Indochina
[8] https://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/french-indochina
[9] https://en.wikipedia.org/wiki/History_of_Laos
[10] https://www.cambridge.org/core/journals/modern-asian-studies/article/abs/french-in-laos-18871945/13C6371000B01530B3011FF9A0B6436C
[11] https://en.wikipedia.org/wiki/French_protectorate_of_Laos
[12] https://www.digitalhistory.uh.edu/teachers/lesson_plans/pdfs/unit12_1.pdf
[13] https://www.pacificatrocities.org/the-french-colonial-period.html
[14] https://www.britannica.com/place/Vietnam/Effects-of-French-colonial-rule
[15] https://www.britannica.com/topic/history-of-Cambodia
[16] https://study.com/learn/lesson/indochina-who-colonized-vietnam.html
[17] https://www.britannica.com/place/Laos/Under-foreign-rule
[18] https://www.jstor.org/stable/45311437
[19] https://www.sciencedirect.com/topics/social-sciences/french-colonialism