To get to North Korea, one can make the rare journey by taking a plane from Beijing to Pyongyang. But for those who have the opportunity, the train offers a unique glimpse of the most closed country in the world.
It is 9:30 am when we leave Dandong, the last Chinese town before crossing the Yalu river that separates the two countries. We are the only Westerners on board the train which takes more than 10 hours to cover the 240 kilometres (150 miles) to Pyongyang.
Dandong is booming, thanks to the border trade that has flourished since North Korea came under international sanctions.
Chinese of Korean descent board the two white and blue sleeping cars, stamped with the emblem of the People's Republic of China. Luggage and packages are piled on the top bunks and in the vestibules at the ends of the carriages.
The contrast between Dandong with its skyscrapers and Sinuiju, the first North Korean town, is striking: the buildings are decrepit, the streets dusty, a small amusement park with rides and a Ferris wheel seems abandoned.
There we see the first statue of North Korea's founding father Kim Il-Sung, who died in 1994 after ruling the country since 1948.
A dozen North Korean customs officers climb aboard. Baggage is searched, and waved over with a metal detector. They note down the number of cameras, video cameras and laptops.
Only mobile phones are forbidden and put in a sealed envelope, with strict instructions not to open it before leaving North Korean territory.
Most of the passengers seem to know the North Korean inspectors.
"I come once a week," said a Korean Chinese wearing a fancy shirt and gold chain, luxury shoes on his feet and a leather bag from a famous French brand over his shoulder.
Once the inspection is complete, customs officers and passengers sit on the couchettes and strike up a conversation.
Cigarettes are passed around and they exchange jokes, punctuated by slaps on the back.
In the corridor, a smiling customs officer questions the four French journalists.
"You've come for the rocket? There will also be foreign experts?" he asked in Chinese.
Clearly, the official media have trumpeted that the forthcoming launch will be covered by dozens of reporters together with some foreign experts.
A dozen faded green carriages bearing the emblem of North Korea are attached to the train.
Soldiers, rifles slung across their shoulders, open the gates giving access to the platform. Hundreds of women bent double under the weight of their khaki burdens and men with bulging bags rush through to the carriages, jostling old people and children.
A "soft seat" North Korean carriage, adorned at both ends with portraits of Kim Il-Sung and his son Kim Jong-Il, who died in December, is attached to the Chinese sleepers. The dining car is right behind. It will act as the "border" to the lower class that the journalists will not have access to.
After the long stop, the train resumes its journey.
The dining car is filled with Chinese traders and members of the elite, mobile phone clamped to ear, shades perched on nose.
The set menu includes grilled fish, beef, rice kimchi and soup, washed down with a glass of warm water. Beer or soju, the local rice wine, is extra.
The North Korean countryside scrolls past the windows. Groups of children wave. The train passes a few vehicles, and men on bicycles too, but not many.
In the well-kept fields, ploughs pulled by raw-boned oxen are more common than tractors.
Here and there appear villages of whitewashed houses with ochre tiled roofs. This region, which borders the Yellow Sea, is considered the rice basket of impoverished North Korea.
As night falls, the villages are plunged into darkness. Only a few windows are dimly lit. Electricity is rationed and residents take advantage of the hours of current to recharge extra lamps.
The train slows down as it approaches the capital Pyongyang, which can be seen in the distance thanks to its lights.
In the city centre, strings of lights shine around public buildings. On the front of the railway station, a giant portrait of Kim Il-Sung is lit all night.