=== Invited talk at the International Conference on Operations Research, September 2017, Berlin === We present the optimization of the new French standard for keyboard layouts. The typical French keyboard layout made it overly complicated or even impossible to type all French characters, punctuation marks, and other symbols. The goal of this new standard was to enable and facilitate the correct spelling of French, and allow the entry of symbols common in programming languages, mathematical expressions, and other European languages. Therefore, we had to assign over 115 characters to 148 slots on the keyboard, optimizing their placement with respect to each other and to the numbers (0-9) and non-accentuated letters (a-z) that were kept unchanged. In interaction with an expert committee, we identified four objectives: input performance and ergonomics, similarity to the prior keyboard, and coherent placement of similar symbols. We collected extensive performance data, language statistics, expert ratings on character similarities, and ergonomic scores to implement and solve a multi-objective quadratic assignment problem. In an iterative process, we computed and adapted a range of solutions in interaction with language experts. The resulting design unifies mathematical bounds with expert opinions and constraints. The new French keyboard layout is the first modern standard where computational optimization methods were used in interaction with domain experts to implement an optimal keyboard design.