For all competition matches, teams must submit the agreed playing attire colours to be worn for each match via the dedicated online tool. The home team has the first choice as to which of its official sets of playing attire registered online it wears for its home matches. The proposed colours will be validated on-site by the referee team.
In any case, if the referee notices on the spot that the colours of the two teams could lead to confusion, a final decision on the colours is taken in consultation with the UEFA match delegate and the UEFA administration. As a rule, in such cases it is the home team that has to change colours, for practical reasons.