There's an extraordinary video doing the rounds at the moment. It shows Mamoudou Gassama, a migrant to France from Mali, scaling the outside of a block of flats, clambering from balcony to balcony. It takes this real-life 'Spiderman' about 30 seconds to reach his goal – a dangling small boy, in imminent danger of falling to his death. He grabs his arm and hauls him to safety.

It's an extraordinary feat of daring, with a gloriously happy ending for the child.

And, it turns out, for Mamoudou as well. France's President Emmanuel Macron invited him to the Elysee Palace, personally thanked him and gave him a medal for courage, promised he would be made a naturalised citizen and offered him a job in the fire brigade.

Nothing that follows should be read as taking away from any of that. Mamoudou is a genuine hero. No one should be anything other than inspired by him and happy for him.

But it's hard not to see his story, in all its hopeful brightness, against the dark background of Europe's long migrant tragedy. They have disappeared from our TV screens, but they are still arriving in overloaded craft in countries that don't want them. Or they are being washed up dead on Greek or Italian shores, victims of cynical people smugglers who send them to see with fake lifebelts and leaky boats. According to Missing Migrants, 639 have died so far this year – way down from its peak in 2015, but each death a tragedy.

And when they arrive in Europe, they don't find an open door and welcoming arms. Poland and Hungary are adamant they don't want them. In Paris itself, 2,500 migrants from Africa, Asia and the Middle East are sleeping rough in three dirty, rat-infested and drug-riddled encampments in the northeast of the city. In mid-May, the archdiocese of Paris denounced the 'total absence of humanity' with which they were being treated.

There are no easy answers to the question of what to do with migrants. But one thing the heartwarming story of Mamoudou Gassama does is remind us that each is a potential hero, with the capacity to save a life and bring tears of joy to the world. They are not, first and foremost, problems: they are people, made in the image of God and infinitely precious. It should not need one of them to risk his life to remind us of their humanity. Most of them have already done that more than once on the way.

Follow Mark Woods on Twitter: @RevMarkWoods