(Reuters) -Shares of Canal+ fell on their London debut on Monday while fellow Vivendi (OTC: VIVHY ) spinoffs Havas and Louis Hachette rose in Amsterdam and Paris, after shareholders of the French media conglomerate voted overwhelmingly in favour of the high-stakes split project on Dec. 9.

Shares of broadcaster Canal+ opened at 290 pence, giving it a market value of 2.9 billion pounds ($3.66 billion), but fell more than 12% from that price to 253.5 pence by 0848 GMT.

Canal+'s decision to list in London, announced in July, was a much-needed boost for Britain's stock exchange which has seen a series of departures and few high-profile joiners in recent years. British finance minister Rachel Reeves on Friday hailed it as a "vote of confidence" in the country's market.

Advertising company Havas rose around 6% to 1.91 euros per share by 0905 GMT compared to their opening price on Euronext (EPA: ENX ) Amsterdam. Publisher Louis Hachette's shares were trading at 1.41 euros on Euronext Growth Paris, up 17.5% on the opening price.

J.P.Morgan analysts had estimated Canal+ to be worth about 6 billion euros, Havas 2.5 billion euros and Louis Hachette around 2.2 billion euros.

Vivendi, backed by the Bollore family, resumed trading on Euronext Paris without the spinoffs and remains a part of the blue-chip CAC40 index for now, though it may exit it at a later date, supervisory board chairman Yannick Bollore said.

Lagardere, majority owned by Louis Hachette following the split, also stays listed on Euronext Paris.

($1 = 0.9514 euros)

($1 = 0.7916 pounds)