Swiss club said the banana had been thrown from the part of the St Jakob Park stadium that was occupied by their supporters.
2018 SeasonAll times ET
Xherdan Shaqiri's former manager at Basel, Thorsten Fink, believes the Switzerland international has world-class natural footballing ability.
Swiss club FC Basel appointed former Austria boss Marcel Koller as their new coach on Thursday, a day after their humiliating Champions League exit.
Roma got a boost for the Champions League group-stage draw when Basel crashed out in the second qualifying round on Wednesday.
Southampton have made their second signing this week with attacking midfielder Mohamed Elyounoussi joining the Saints on a 5-year deal from Basel.
Ajax have announced the signing of Dusan Tadic from Southampton, who have lined up Basel's Mohamed Elyounoussi as a replacement.
Leicester are planning a move for Basel star Mohamed Elyounoussi after seeing competition from Bayer Leverkusen, sources have told ESPN FC.
Paris Saint-Germain have been hit by four different UEFA charges following their 2-1 loss at home to Real Madrid in the Champions League.
Arsenal, Leicester and Southampton are weighing up moves for Basel star and Norway international Mohamed Elyounoussi.
A rotated Man City came up losers against Basel in their second leg, but Pep Guardiola's side look more than ready to face stiffer challenges ahead.
Manchester City wrapped up their straightforward passage into the Champions League quarterfinals 5-2 on aggregate after a 2-1 loss against Basel.
Basel coach Raphael Wicky hopes his side can do themselves justice when they face Manchester City again on Wednesday.
Man City were too much for Basel in every way, as again Kevin De Bruyne showed he belongs in the company of the world's best, writes Jonathan Smith.
Manchester City have a decisive upper hand in their Champions League round-of-16 tie after beating Basel 4-0 at St Jakob Park.
Basel might be tempted to use Dimitri Obertin as their secret weapon against a potentially vulnerable Manchester City on Tuesday.
Basel coach Raphael Wicky is confident his side can spring a surprise against runaway Premier League leaders Manchester City.
Which eight clubs will make it through to the Champions League quarterfinals? Here are our writers' predictions.
Borussia Dortmund have signed former Liverpool target Manuel Akanji from Basel for a reported €21.5 million fee including bonuses.
Director of football Txiki Begiristain insisted Manchester City will "have to be careful" after being drawn against Basel in the Champions League.
The draw for the Champions League round-of-16 has been made, and there's one clash that stands out as Neymar's PSG take on champions Real Madrid.
The business end of the Champions League starts here. The draw for the round-of-16 has been made, and there's a bunch of intriguing clashes.
Ties for the Champions League's round of 16 will be played Feb. 13, 14, 20 and 21 and March 5, 6, 12, 13.