If you are likely to be visiting someplace where French is the first spoken language, then it is sensible to master just a little French beforehand. This implies taking the time to learn the language. And believe me, it does take a bit of time to be fluent. If you do not have this time what alternatives are open to you ? What's the easiest way to master French prior to visiting ?
Some basics: Foreign language courses are quite different from other courses so you must never drag your feet about it. Any postponement is deemed as a failure in a foreign language course where you need to devote a minimum of 15 minutes a day for a minimum of 3 hours a week. While you need not put in more than 45 minutes learning the language in one session, try to accommodate all the extra time you have in your hands.