1) What to wear: In August, most areas in France, Switzerland and Italy are very hot, especially in southern France and Italy. It belongs to the Mediterranean climate, and it is usually sunny and very hot! Except the Alps in Switzerland and France! In mountainous areas, it is also very hot at noon, and summer clothes are fully competent, but it will be cold sooner or later. Therefore, without knowing your specific itinerary, I can only suggest that you mainly take summer clothes, but if you have a mountaineering trip (such as Jungfrau, Mont Blanc, and Mount Titlis, etc.), you can take a few autumn clothes. Why? Because as long as you are young and strong, such as going to Mount Titlis, I see many people wearing short sleeves. So you can decide whether to bring "late autumn" clothes or "early autumn" clothes according to the length of your stay in the mountains.
2) What to bring: There is no special need to pay attention to the area you want to visit. Just like going to other places, you should bring whatever you need to bring when you travel, such as necessary medicines and slippers. Since it is August and the sun is shining, it is recommended that you take sunglasses and sunscreen, because these countries are basically outdoor visits, and there are also trips such as beaches and snow-capped mountains, so it is necessary to take sunscreen!
3) What to buy: Hehe, this question is very interesting! I just read a report this morning that Chinese tourists are the king of shopping in France. I don't have those high-end purchasing power, so I can only give you some advice from the perspective of "special souvenirs"
First of all, France: perfume, fashion, leather bags ... these are all high-end, but in fact, as long as they are not very expensive, the prices are really not much cheaper than those in China. Red wine can be bought in China as long as it is not a very high-end brand or year. Therefore, I suggest that you don't have to buy anything deliberately in France, as long as you meet special favorites according to your hobbies, such as various plant essential oils, foie gras, COGNAC brandy, etc.
Next is Switzerland: Watch, let's not talk about this thing. I can only say that Tissot belongs to only one civilian brand in Switzerland. If it goes up, Longines, Omega, Jaeger-LeCoultre, Vacheron Constantin and Patek Philippe ... it depends on your personal hobbies and actual purchasing power. But I must say, because of the tax refund, these famous watches were bought in Switzerland, one of which is guaranteed in quality, and the other is really much cheaper than in China! Besides, the Swiss army knife, I want to buy this one, and I must buy it in Switzerland! Swiss army knives are really cheap, cheaper than neighboring countries! In addition, I want to buy the "Cowbell", which is a souvenir with the most Swiss folk characteristics. It is of different sizes, memorable and inexpensive. Finally, there are two things to mention, that is, the music box and the cuckoo clock. In fact, the music box is a masterpiece of the Swiss. The music box originated in Switzerland is really exquisite, just like her watch, but it is also expensive. If you like it, it is really worth buying. Although cuckoo bells can be seen everywhere in Switzerland, they are not Swiss specialties, but German black forest specialties, so it is not recommended to buy them!
Besides Italy: please remember! Don't buy any glass, ceramics or leather crafts that the tour guide asks you to buy! The quality is high, and their so-called "famous factories and workshops" are all nonsense! If you really like certain shapes of handicrafts, it's much cheaper to buy them in small shops on the street! But I have to say that the glass products in Venice and the leather products in Florence are really famous. In addition, I suggest you buy Italian "masks", which are very Italian handicrafts.
4) Free activities: In Italy and southern France (or big cities), I advise you not to go out alone at night, because there will be many ronins and drunkards in the streets at night. In fact, the law and order in Italy is not very good, and there are many thieves, especially in Rome, which is very chaotic. You must pay attention! If you go out for a walk at night, it's best to go back to the hotel at 23 o'clock, so don't bring your passport. Generally, you won't check it. As for the place to go, I suggest you choose a small bar, a small coffee shop and a small restaurant and try the most authentic local food or drink. For example, in France, you can order a cup of coffee, a cup of Cidre, a cup of blended Cognac, a croissant, a plate of salad, a plate of cheese, a plate of North African olives, a plate of fresh oysters ... these are very authentic "snacks" and "nightlife"; In Switzerland, you must eat "Cheese Hotpot" and "RACLETTE". I can't guarantee that you must be used to the taste of cheese, but this is definitely the most Swiss food. By the way, you must buy a bottle of Rivella, which is made from whey extracted from milk. The Swiss "national drink" has four flavors; In Italy, pizza and spaghetti are famous. There are so many flavors that you can choose according to your own preferences. There is a kind of "cuttlefish spaghetti" that you must try. After eating, your mouth is all black and has no flavor. Haha!
The above answers, I hope to help you! Good wishes!