There are a total of 54 ethnic groups in Vietnam.
The portraits he’s captured provide a glimpse into the vanishing cultures of people who are striving to hold onto their heritage in a rapidly-changing world.
Keep scrolling to see breathtaking photos of some of Vietnam’s most remote tribes.
Although he's originally from France, Réhahn currently lives with his family in Hội An, in central Vietnam.
Réhahn predicts he'll need two more years to finish photographing the remaining 14 tribes of the country that he hasn't seen yet.
He explains the villages are often lost in the mountains, and there's no existing information -- in English or Vietnamese -- about how and where to find them.
Once he reaches a tribe, Réhahn spends time listening to the elders' stories and capturing where they live.
At the same time, the elders are sad because the pride they feel for their heritage is not present in the younger people of the tribe.
He says that so many people are completely oblivious to the fact that entire cultures are dying around them.
'It's as if a part of cultural history is going to sleep forever and no one seems to be doing anything to wake it up.'
This 78-year-old woman is the last remaining person in Vietnam who still makes the traditional costume of the Ơ Ðu tribe. There are only about 500 Ơ Ðu members left in the world.
The photographer feels that if these people see their culture through someone else's lens, it might help them to grasp the importance of it.
'We know that we often have to look back before we can move forward and how wonderful it would be to remind people of the beauty of their unique cultural legacy.'
His goal is to build a cultural ethnic museum in Hội An and display his photos, the costumes, and these people's stories.
Business Insider Emails & Alerts
Site highlights each day to your inbox.