[1] Garrison duty in French Indochina proved to be a fairly peaceful assignment for the legionnaires until the outbreak of World War II with the notable exception of the Yên Bái mutiny in 1930.

The 5th Foreign Infantry Regiment rotated its battalions to execute major construction works, one of which was the strategic route between Campha and Tien Yen.

The legionnaires were in charge of the supervision of local inhabitants, but also contributed to the construction of pasture centres in Mont Bavi and Khang Kay (Laos), as well as the expansion of those in Chapa and Tam Dau.

The 2nd Battalion assured a part of the garrison of Lang Son and Dap Cay, while the motorized detachment joined Cao Bang.

[2] Accordingly, the 2nd battalion, in garrison at Fort Brière de l'Isle, mounted defensive measures under the orders of Commandant Marcelin.

In February 1946, the legionnaires were authorized to cross the Tonkin frontier, to push the Viet Minh, their new adversary, approaching Son La.

Linked to the exterior world only by radio and parachuting, they succeeded in June to reach the province of Sam Neua, which they protected against looters.

At the moment were the war in Indochina was developing, the 5e REI was set back on foot in Tonkin on November 1, 1949, from the V/4th Foreign Infantry Regiment and effectifs from Sidi bel-Abbès.

The new mission of the 5e REI was to defend the frontier north-east of Tonkin, and principally the axe route which linked the Mon Caï sector to the Delta.

The unit collected the debris of colonnes Charton and Lepage as well as the echeloned garrisons along the pressure axes of the Viet-minh (Battle of Route Coloniale 4).

Until the month of November, the life of the pioneers (French: Les Pionniers) followed, opening of routes, ambushes, harassment and regulated attacks.

The unit remained until April 6, 1953, organizing continuously positions, constructing and building roads to unnerve the adversary, and enduring while repelling ongoing increasing attacks.

In the Delta, operation followed in September 1953, then October 15 in the region of Phu Nho Quan and the sector of Dong Qui Thon as well as Trai Lai Vi.

In March 1954, the 5E REI was represented at Dien Bien Phu, by the 2nd Mixed Heavy Mortar Company 2e CMML and by 80 volunteer legionnaires to be parachuted «pour l’Honneur».

On December 4, 1960, the regiment replaced the 13th Demi-Brigade of Foreign Legion 13e DBLE at Bou Hamama, in the Constantinois, then the 3e REI in Kenchala.

In May 1961, a new operational phase commenced along the barrage to refix, protecting the electro-mechanical, clear the barbed wire networds from the snow, and regulate instances of fire.

Finally, in March 1963, the 5e REI was transformed into a legion engineer unit (French: unité de Génie Légion) and prepared to depart to Polynesia.

On April 30, 1964, in preparation for the celebration of Camaron, the 5e RMP received a new insignia which recalled the original place of garrison, its belonging to the Legion engineer function, and in the implantation in Polynesia.

Personnel of materials arms and Troupes de marine were assigned to the regiment and 400 Polynesian civilians came forth to reinforce formation.

In August 1965, the peripheral post installations whose mission was to observe the weather, were protected by detachments of the 5th Mixed Regiment of the Pacific, 5e RMP.

The 5th Mixed Regiment of the Pacific conducted infrastructure installations works relative to land, naval and aerial armies.

Regrouped at Moruroa on January 5, 1976, the 5th Mixed Regiment of the Pacific 5e RMP dived in total unknown autonomy along with French nuclear experimentations.

The regiment executed backfilling for the openings of littoral defenses on Utufu, Malefo’ou, Walmalau, Kolopopp and Tees, restructured and automated the climatic observation posts of Tureia in 1986, and reconstructed the port dike of Hakahau and the Marquise islands in 1988.

During this period, the regiment partook to the repair of routes, the extraction and crushing of aggregates, operations of maintaining order and the construction of hangars related to local cooperation.

The 5th Foreign Regiment 5e RE reinforced the bedrock of Whalf Halalo, opened a field at Lavegahau and Haatofo, leveled the ground for the emplacement of the hospital of Alo along with the incorporation of numerous sports terrains in each village, dynamited the passages of Vele, Alofi, Taua, Ono Tuatafa, Kolia, Tavai and Sigave, built an omnisports at Mangareva in 1993, an aerodrome at Takume in 1994 and 1995, the field of Ahe from 1995 to 1996, the aerodrome of Hikueru from 1996 to 1999 and participated the repair and enlargement of the principal route on the atoll of Takapoto in the summer of 1999.

End of June, the legionnaires welcomed a company of the 8th Marine Infantry Parachute Regiment 8e RPIMa, inbound for reinforcement of the securitization of the airport at Faa’a.

After being placed under the orders of the director general of the center of nuclear experimentation (DIRCEN), the regiment passed on August 1, 1998, under the subordination of superior French command of Polynesia (COM SUP) at the corps of the sovereign forces.

This mission consisted of two wings: the participation to exercises, maneuvers and turning presence, organized by the COM.SUP and the intervention to aid local populations in case of natural calamity.

Vaillants guerriers de ce Régiment Vous qui luttiez si superbement En maintenant dans la tourmente L’Honneur et la Fidélité Vos successeurs ont serré les rangs Donné leur cœur et versé leur sang En combattant sans épouvante Pour le 5e Étranger

Le front haut et l’âme fière Marchant du pas de nos anciens Nous suivons dans la poussière Un glorieux chemin La boue sombre des rizières Scella notre destin Donnant ce nom qui sonne clair Régiment du TONKIN