• Shares in French broadcaster Canal+ fell almost 16% following their London stock market debut Monday.
• Canal+ is a pay TV and production company known for its live sports broadcasting and Studiocanal, which makes the Paddington film franchise.
• Shares were trading around 252 British pence ($3.19) at 9:13 a.m. London time, down 13.1% from the open.

Shares in French broadcaster Canal+ fell almost 16% after their London stock market debut on Monday.

Media holding company Vivendi's shareholders last week agreed to spin off Canal+, a pay TV and production company known for its live sports broadcasting and Studiocanal, which makes the Paddington film franchise.

Shares were trading around 243 British pence ($3.07) at 10:13 a.m. London time, down 15.7% from the session's open.

Paris-listed shares of Vivendi were meanwhile up 33.2% at 10:13 a.m. London time.

"Vivendi was suffering from a conglomerate discount. So when you looked at the value of Vivendi, it was less than 10 billion euros [$10.52 billion], and the estimate of the sum of the parts was much greater than that. So to unlock that value potential of each of these assets, hence the split," Maxime Saada, CEO of Canal+, told CNBC's "Squawk Box Europe" Monday.

"[Canal+] used to be a very French-centric company, with approximately 9 million subscribers, and, in just 10 years, it has tripled its number of subscribers. Now two-thirds of our subscriber base is outside of France, in Africa, in Eastern Europe, in Asia, and, of course, in France," he said.

Saada added that the spun-off Canal+ would seek to expand its presence as a sports broadcaster to compete with U.S. players in a selective manner.

"Every company that I've seen in our business that has really died is because they overspent on sports," he said. "We're not dependent on any kind of content, any piece of content. Because we have this broad value proposition with cinema, with sports, with the platforms, we can pass on rights when we believe that they're too expensive."

Havas and Louis Hachette Group are also being spun off from the Paris-headquartered media conglomerate and will be listed on the Euronext Amsterdam and the Euronext Growth Paris, respectively.

"We are delighted with the very high adoption rate of our spin-off project. This undisputable result confirms the strong support of our shareholders for this transformative transaction," Yannick Bolloré, chair of Vivendi's board, said in a statement last week after the plan was approved, with over 97% of votes in favor.

The Canal+ London listing was seen as an avenue to provide a much-needed boost to the U.K.'s capital markets following a slew of departures over recent years. Chancellor Rachel Reeves on Friday described the debut as a "vote of confidence."

"I'm delighted that CANAL+, a leading international media company, has chosen the UK. Their decision is a vote of confidence in the UK's capital markets, the stability we are delivering and our plan for change," she said in a statement at the time.

It comes as the London Stock Exchange looks set for its worst year for departures since the financial crisis, according to an FT report citing the LSEG, which indicates that a total of 88 companies having delisted or moved their primary listing from London's main market this year, while only 18 have joined.

The LSE departures have taken place despite government and regulator moves to boost the London's appeal as an investment hub and reform listing rules in a bid to compete with competitor markets, particularly in the U.S.

"Choosing London for Canal+ is important as it is the biggest company to join the UK stock market since changes to the listing rules in the summer and under the newly installed Labour government," Russ Mould, investment director at AJ Bell, said over email.

"If Canal+ does well, it could act as a shop window for other big names to float in London and help replenish the pot that has been shrunk by takeovers and delistings," he added.

Investors will now be closely watching the fate of other potential U.K. listings, including that of Singapore-based fast fashion giant Shein. The online fashion group has been engaged in ongoing discussions with the British government after shelving its flotation bid in the U.S. amid pushback over its ties to Beijing and broader labor practices.