Police say the foreigner was killed in Aileron, about 135km north of Alice Springs, at 5.30pm on Wednesday.
"It is believed that two French tourists, being husband and wife, were at a rest stop 30km south of the Aileron Roadhouse on the Stuart Highway when they were approached by an unknown man," Detective Superintendent Travis Wurst said.
"The man has allegedly then stabbed the male tourist to the neck, in an unprovoked attack. The male passed away at the scene."
The attacker then allegedly escaped in a car but was soon stopped by police near Ti Tree.
The man then fled on foot into bushland and was arrested about 8:30am on Thursday nearby.
"The partner of the victim is currently at Alice Springs Hospital where she is being treated for shock," Detective Superintendent Wurst said.
"A crime scene will remain in place for the remainder of today. Police will continue to speak to a number of witnesses to establish the exact circumstances surrounding the death."
