French and Swiss prosecutors say they've dismantled a major drug trafficking and money laundering network, arresting 20 people on Wednesday, including employees of a finance company and major international bank.

The network, largely members of an extended family that imported Moroccan drugs for sale in France, laundered millions over many years, according to prosecutors, who described the family as "masters of financial engineering." The ring included at least one employee at a major international bank, the Swiss said.

Police searches in France netted cash in dollars and euros, accounting documents, counting machines and weapons. In Switzerland, authorities found 160 luxury watches and jewelry worth nearly €1 million ($1.3 million), as well as cash.

Paris prosecutors said between May and October alone, nearly €12 million ($15.5 million) passed through the network.