Comment gérer l'indice de peur et de cupidité ? Comment l'interpréter et le comprendre correctement ?

Hey Silent, it also fascinated me at one time. It's the idea of medium tv CNN. The Fear and Greed Index is a way to measure stock market movements and whether stocks are valued fairly. The theory is based on the logic that excessive fear tends to drive down stock prices, and too much greed has the opposite effect.
The index is a mix of seven different indices that measure some aspect of stock market behavior: market dynamics, stock volumes, stock price ranges, put and call options, demand for junk bonds, market volatility and demand for safe indices.
The index tracks how far these individual metrics deviate from their averages compared to normal averaged metrics. The index gives each indicator equal weight in calculating a score from 0 to 100, with 100 being maximum greed and 0 signaling maximum fear.
The index is counted when new data is published.

Recently, it has become important in the valuation of market sentiment measurement. Many investors are emotional and reactionary, and Fear and Greed sentiment indicators can alert investors to their own emotions and biases that may influence their decisions. Combined with fundamentals and other analytical tools, the Index can be a helpful way to gauge market sentiment.
so it is not a public measurement tool, it is owned by the CNN media network and published on https://edition.cnn.com/markets/fear-and-greed

Which market are you talking about exactly? The Fear and Greed Index is used, for example, in the cryptocurrency market. It shows the current mood of investors. Extreme fear can be a sign that investors are very anxious, so there is an opportunity to buy cheaply. On the other hand, a high greed index means that the market is facing a correction, the only question is when.
It can be observed, among others, here: https://alternative.me/crypto/fear-and-greed-index/. The update takes place at midnight, and the indicator itself is based on Bitcoin. Among the variables that are taken into account to determine market sentiment are: BTC price fluctuations in relation to the last 30 and 90 days, purchase volume compared to the previous 30 and 90 days, interest in social media during the day, decrease or the rise of Bitcoin's dominance and the analysis of some queries from Google Trends.
It is not a perfect tool, but sometimes it can be useful when making sales decisions. It allows us to compare whether our feelings are similar to other market participants, or whether fear or greed blind our eyes. However, to be sure, it is worth being guided by several indicators, not one.

Straight:
With Extreme Fear you buy, with Extreme Geed you sell :)
I use too
https://alternative.me/crypto/fear-and-greed-index/

Hello everyone :) Thank you for your answers. They're great :-D First of all, I'd like to apologize for not responding for a long time, because I took a vacation in dealing with some topics. During that time I was working on other things and running errands. Returning to the subject of this question, I mainly meant cryptocurrency markets, because I have been investing in them for several years.
Someone once said or wrote somewhere: Having some experience in investing in one stock exchange, you can manage quite calmly in various other stock exchanges and markets. - That's how it went more or less, because I don't remember who, where and when formulated this statement, so I took the liberty of taking it out of context and quoting, or at least paraphrasing it here. I think this person was quite right about that, because for a while I invested small amounts in regular fiat currency, using the services of one of the online exchange offices, which has line charts for all exchange rates available there. And even from symbolic amounts of up to ≈50 zlotys, I managed to earn small profits of up to PLN 2 over a slightly longer period of time, ranging from several months to about a year due to small exchange rate fluctuations, taking into account the possibility of breaking through the spreads. I do not yet have experience in investing on traditional stock exchanges and/or on the stock markets of various listed companies, e.g. FOREX or in topics related to futures contracts and similar matters, but maybe someday, in some unspecified future; who knows :)
Nevertheless, it is worth noting the links you provided to these indicators. Someday, they can certainly be useful to check the sentiment assessment on the cryptocurrency markets, because there is no doubt that Bitcoin was and still is the leader among cryptocurrencies, and altcoins and all the rest of these assets reflect its movements.

To understand the Fear and Greed Index, it is worth first understanding that this indicator measures the emotions of investors in the market. The higher the level, the greater the greed, and the lower the level, the greater the fear. Therefore, it is important to track this indicator as one of many tools for market analysis. When interpreting the indicator, pay attention to its absolute value and changes over time. If the indicator is at a high level, it may indicate excessive optimism and an upcoming correction. Conversely, a low level may indicate pessimism and a potential buying opportunity for stocks. To check the Fear and Greed Index online, it is worth visiting the money.cnn.com website, where the current indicator and its interpretation can be found. On this website, you can also find charts and analysis related to the financial market.