Geneva police launched a major operation yesterday after an attempted robbery on the Rue de Rhone.
Reports suggest one person was held hostage for a while when the robbers hit a high-end jewellery shop just before midday.
One man was arrested near Rive, but others are thought to be on the run.
Heavily armed police searched trams heading towards Carouge.
Police are confirming one person is in custody, but are not releasing any further information.