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Most founders ask how to find an audience. Arnault asked a different question: who already has one, and what would make them share it?
Arnault is a French entrepreneur based in Paris and the founder of Brainstorm Media, a network of newsletters and Instagram accounts about business, the economy, and tech. The page header puts revenue at $20K a month, while the article body says 20,000 euros a month at its peak, so treat the figure as approximate. The business started in May 2022, grew to five brands, and was acquired in 2025.
The story is useful because the growth tactics cost almost nothing. Here is how it worked.
A Market With No Competition
Arnault wanted to write online, so he launched an entrepreneurship newsletter inspired by Starter Story. He reached 1,000 subscribers by messaging friends, colleagues, and his LinkedIn network, and then a brand paid 100 euros for a sponsored article.
Around the same time he studied the case studies on Morning Brew and Milk Road and concluded that newsletters could be a real business in France, where almost nobody was doing it. He went all in, quit his job, and launched a personal finance newsletter, then a crypto one.
Fifty Messages a Day
The early months were manual. He sent about 50 LinkedIn messages a day for a month, and LinkedIn restricted his account several times. He also contacted every business and finance creator and newsletter he could find, by LinkedIn and by email.
The first 100 euros took about three months to arrive, when a reader asked for a sponsored article. Selling newsletter sponsorships in France was hard, which shaped the next move.
Borrowing Other People's Audiences
Two tactics did most of the work, and neither needed a marketing budget. The first was Substack Recommendations. He contacted every French Substack writer he could find and proposed that they recommend each other, and he credits that feature with tens of thousands of subscribers at no cost. The timing helped, since Substack was nearly unused in France and the feature had just launched.
The second was Instagram affiliates. Influencers shared a lead magnet in their Stories, and he gave them part of the sponsorship revenue it generated. There was no upfront cost. His rule, as he describes it, was never to pay for attention first, but to find people who already had an audience and give them a good reason to share it.
Buying Small Media Instead of Building From Zero
Newsletter sponsorships were hard to sell in France, but Instagram content sold more easily. So he bought small business, tech, and finance Instagram accounts and grew them, and they fed readers back into the newsletters.
What the Revenue Looked Like
At its peak the network had five brands and made around 20,000 euros a month, mostly from sponsorships with large French brands such as Peugeot. The team was Arnault plus ten employees. The article does not cover costs, profit margins, pricing, tools, or the terms of the 2025 acquisition, so those details remain unknown.
The One Thing He Did Not Build
His biggest mistake was relying only on sponsorships and never launching a product of his own. If he started again, he says he would build a product himself or partner with an entrepreneur who could. For a business that earned from a single source, that is a candid admission.
What He Tells Other Founders
He suggests building on knowledge and passion you already have instead of copying American startups. He reads daily and says many of his best ideas come from books, newsletters, and case studies. His view on action is blunt: nobody is going to save you or your business, so if you need an answer, send the email, the LinkedIn message, or make the call.
A few things worth taking from the story:
Look for who already has the audience. A recommendation swap or a revenue share costs far less than ads and brings readers who already trust the source.
Pick a market that is still empty. France had almost no newsletter competition, and the timing of Substack Recommendations amplified it.
Own something besides the sponsorship. A single income source is the weak point he would fix first.
What Comes Next
Brainstorm Media was acquired in 2025, and the article gives no further plans. The lesson he leaves behind is simple: luck comes to you when you are in the game, not when you wait at home.
Credit and sources: this edition is based on the Starter Story interview with Arnault of Brainstorm Media. You can find the network at brainstormmedia.org.
