If you run an online shop, a translation into French might be useful for this reason:
Within a one-month period in the last quarter of 2016, 62% of people living in France bought goods online. That put France in seventh place, just ahead of Canada which occupies place eight with 60%. And Canada itself is also partly French-speaking.
Something else to consider: 37% of people in France bought clothes and sporting goods online in 2016. So if you offer fashion or lifestyle products, having your online shop translated into French might just win you many new customers.