PARIS — The latest standoff between Europe and American tech companies runs through a quiet street just north of the Louvre Museum, past chic cafes and part of the French national library, to the ornate office of Isabelle Falque-Pierrotin.
From here, Ms. Falque-Pierrotin has emerged as one of the most important watchdogs for how companies like Facebook and Google handle the billions of digital bits of personal data — like names, dates and contacts — routinely collected on Europeans. Since 2011, she has been France’s top privacy regulator, and for the last two years, she has led a group of European data-protection officials. In those posts, Ms. Falque-Pierrotin has regularly agitated companies to better safeguard people’s data.
Her role will come into even sharper focus in the coming weeks. Ms. Falque-Pierrotin, empowered by Europe’s highest court, will be at the heart of efforts to police how digital data is transferred outside of the European Union, a central aspect of many European and American businesses. That role will be amplified even further if, as is now widely expected, American and European negotiators fail to reach a new data-transferring deal by Feb.