Apple Faces French Antitrust Complaint From Online Advertisers

Apple Inc. faces a complaint from a group of French online advertisers who want the country’s antitrust authority to halt the U.S. tech giant’s potentially “devastating” changes to how iPhone users’ data is collected.

Publishers’ ad revenue could plunge by as much as 50%, marketers won’t be able to measure campaigns and ad-funded apps may need to move to a user-payment model following the overhaul, a coalition including IAB France, MMAF, SRI and UDECAM warned in a statement on Wednesday.

While the changes are part of Apple’s efforts to increase privacy and data security, advertisers say they don’t comply with ...