After Borussia Dortmund's fans opened their doors to Monaco rivals stranded by a bomb attack that postponed their match, the visitors returned the solidarity gesture Wednesday decked out in the German squad's black and yellow.
All day Monaco fans piled into the German club's boutique, snapping up Dortmund gear before kick-off.
"We've sold hundreds of scarves and jerseys since this morning, and it's almost only the French who've been buying," said Sultan Karakas, who was manning the boutique's till.
Monaco may have won 3-2 in the end -- much to the annoyance of Dortmund coach Thomas Tuchel, who said his shaken players should have had more time to process the attack -- but the visiting team's fans had already won their hosts' hearts earlier in the day.
Social media lit up with photos of Monaco and Dortmund supporters sharing beers and snacks in a display of camaraderie rarely seen between rival teams.
Arthur Glapa, a Monaco fan who spent Tuesday night in his car with a friend so that he could catch the rescheduled match, said he had been struck by the sense of solidarity.
"I like them a lot," the 22-year-old said of the German fans. He had had his replica Monaco shirt freshly printed with the name of Marc Bartra, the Dortmund defender injured in the blasts that hit the Borussia's team bus, shattering the vehicle's windows.
"At first they did not want to print (Bartra) on a Monaco jersey, but the store manager intervened," Glapa said.
Police ramped up security around Signal Iduna Park -- likewise for the Bayern Munich fixture against Real Madrid in Munich -- but the boosted police presence appeared to reassure match-goers.
"There are so many police here that we feel protected -- we're not scared, we're going to enjoy the match," Dortmund fan Sven Bude said.
In the stadium, the rows of Monaco fans were noticeably thinner than a night earlier -- many having had to return home after the match was put back -- but they and their players received warm applause from their hosts before kick-off.
Monaco supporter Julien Nedjar, one of those who decided to stay, said it sent a powerful message.
"We were there to party," he said. "It must not be them (the terrorists) who win."
- 'Beautiful moment' -
Boris Marchi, 26, who knotted the red and yellow scarf of his club Monaco to the yellow and black of Dortmund, told AFP he had been offered lodging by a German supporter.
"It was really a beautiful moment," he said, adding that he was meeting his benefactor for a drink before kick-off.
With the Twitter hashtag #bedforawayfans, Dortmund supporters offered many of the 3,000 visiting fans a kip for the night, while Borussia Dortmund's official account also promoted the initiative.
"It's obvious: if we were stranded somewhere abroad, we would have also wanted to have some accommodation made possible," Dortmund fan Renke Reichler told Munich-based paper Suddeutsche Zeitung.
Reichler and his wife took in five Monaco fans, and have been invited to Lille as a thank you.
The Monaco contingent had been praised for their gesture in chanting "Dortmund, Dortmund" after the attack was announced in the stadium just before kick-off was due on Tuesday night.
Chancellor Angela Merkel praised fans for their "calm" behaviour and the host side for their hospitality, while former Arsenal and England striker Ian Wright said on Twitter "I love this football club (Dortmund)" in a reference to #bedforawayfans.