There is no time difference between Zurich and Paris. Both cities use Central European Time (CET/CEST, UTC+1/+2). When it's 12:00 PM in Zurich, it's also 12:00 PM in Paris.
Both cities observe daylight saving time on the same schedule, so they remain synchronized year-round.
Any time works! Since both cities share the same timezone, you can schedule calls during standard business hours (9:00 AM - 6:00 PM) without any time conversion needed.
Zurich and Paris are neighboring European financial centers with strong business ties. Switzerland and France share a border, and the French-speaking part of Switzerland (Romandie) has particularly close cultural connections to France. Direct trains connect them in about 4 hours.