The guests invited to the ceremonial signing of the "Istiqlal Declaration" by Pope Francis and Grand Imam Nasaruddin Umar wear colourful batik clothing.
Batik - derived from the Javanese "mbatik" (to write with wax) - is an expression of national pride in Indonesia.
Francis, meanwhile, has appeared in his white cassock - just as the Grand Imam is dressed entirely in white. The colour of light is not the only thing that unites the two religious leaders on this Thursday.
In their joint declaration, they call for action against violence and environmental destruction.
Unfortunately, wars and conflicts are often fuelled by the instrumentalisation of religion. The global environmental crisis has also become an obstacle to the coexistence of peoples. Against this backdrop, religion must promote and protect the dignity of every human being.
"Since there is a single global human family, interreligious dialogue should be recognised as an effective instrument for resolving local, regional and international conflicts," the document states.
"Tunnel of friendship" connects church and mosque
Another symbol of togetherness is the new subway connecting Indonesia's huge Istiqlal National Mosque with the much smaller Catholic Cathedral of the Assumption of the Virgin Mary on the other side of the road.
However, the health-impaired Pope Francis, who is dependent on a wheelchair, left it at a glance at the entrance to the "Tunnel of Friendship".
The appeal signed by the Pope and the Grand Imam is supported not only by Catholics and Muslims, but also by Buddhists, Hindus, Protestants and representatives of Confucianism. They all belong to the religious communities officially recognised by the constitution. Indonesia's indigenous religions, which are practised by around 20 million people, are not recognised.
Thanks to a ruling by the Constitutional Court, these people have at least been allowed to enter "Penghayat Kepercayaan" - believer - in the "Religion" column of their identity card since 2018. Previously, the authorities automatically entered "Islam".
While the "Declaration of Istiqlal" is being signed in the tent, thousands of onlookers have gathered outside to catch a glimpse of the Pope. Excitedly, they pull out their mobile phones to take a snapshot of the head of the Catholic Church.
A Muslim, who introduces himself as Edi, holds the yellow and white Vatican flag in his hand. "Paus good!" he shouts. "Paus" is Indonesian for Pope. A young Catholic boy holds up a piece of cardboard on which he has written in bright colours in Italian: "Papa, lascia che ti tenga la mano" - Pope, let me hold your hand.
Vatican security guards are horrified
As Francis leaves the event, there is no stopping the crowd. Hundreds rush towards the 87-year-old's white Toyota - hoping to reach his hand through the open car window. Some female spectators scream as if the star of a Korean boy band is driving past.
The visibly overwhelmed police barely manage to hold back the crowd. Sheer horror is written all over the faces of the Vatican security guards to the right and left of the car.
Augustinus Bandur is a little disappointed that he was barely able to see the Pope. The lecturer at Binus University in Jakarta has written a book about Francis, which he proudly shows off.
Somewhat loosely translated, the title is: "Leadership - The Authentic Pope Francis - A Role Model for the 21st Century World".
"Two bishops have written forewords," says the man from Flores, the only Indonesian region with a Catholic majority.
However, his words are almost drowned out by the honking horns of the many cars. The drivers are not greeting the Pope. They are expressing their anger because the roads around the cathedral and mosque are closed to the Pope's convoy.