ChatGPT : qu'est-ce que c'est et comment l'utiliser ?
- Stéphane Guy
- 1 day ago
- 7 min read
OpenAI has extended voice recognition to all users, including those on the free tier. Whether you're a first-timer or a power user, here's everything you need to know about ChatGPT: how it works, what versions exist, and what you can actually do with it.
In short
ChatGPT is a conversational AI developed by OpenAI, capable of generating natural, contextually relevant text responses.
It understands questions, simulates dialogue, and assists with a wide range of writing and reasoning tasks.
Built on the GPT-5 architecture, it leverages machine learning to continuously improve its outputs.
ChatGPT is deployed across industries, from customer service and content creation to education and software development.
It's available in free and paid tiers, with advanced features unlocked through Plus, Pro, and Team subscriptions.
What Is ChatGPT?
ChatGPT: The AI Built by OpenAI
ChatGPT is an artificial intelligence system that takes the form of an internet chat interface, more precisely, a conversational agent. It was built by the San Francisco-based company OpenAI and made publicly available on November 30, 2022. Its core function: engage users in dialogue to provide advice, information, and answers to their questions. To do this, OpenAI's model draws on hundreds of billions of data points sourced from across the internet to build and continuously update its knowledge base.
Getting started is straightforward. Head to chat.openai.com, create an account or sign in using a quick-connect option like your Google account, and you're in. Any modern browser, Chrome, Firefox, Edge, Brave, will work.
Not sure about the terminology? Our AI glossary covers every key concept you need to navigate the AI landscape.
What Versions of ChatGPT Are Currently Available?
As of May 2026, ChatGPT has moved beyond the GPT-4 era. The platform now operates primarily on the GPT-5.5 series, which replaced GPT-4o and the initial GPT-5 models earlier this year.
What subscription plans are available for ChatGPT?
There are four main subscription plans for the general public: the free version, the “Go” plan at $8 per month, which lets you chat with ChatGPT for longer, send more documents to use in conversations, or ask it to generate more images. It also features improved memory to better recall your conversations.
Next is the “Plus” version at $23 per month, which gives you the 5.5 Thinking model instead of the 5.5 Instant model. In addition to enhanced memory, image generation, and the ability to upload even larger documents, you’ll be able to customize GPTs, access Agent Mode, get early access to preview features, and use Codex, the AI’s advanced computer coding feature.
Finally, there’s also the Pro version for $103 per month, which includes the 5.5 Pro model, unlimited access to image generation and document uploads, maximum memory, and unlimited access to all other features.
In addition, there is a Business plan available for $21 per month per user, which includes all the features of the Plus subscription as well as the Business Codex plan. You’ll also have access to over 60 apps to boost your productivity, as well as business features such as data analytics. The workspace will be secured with administrative features to configure and set up the space for your team or company. Finally, no data will be used to train artificial intelligence, and you’ll have access to support that complies with GDPR, CCPA, and other privacy laws. Aligned with CSA STAR and SOC 2 Type 2.
For businesses operating at scale, you also have access to the Enterprise subscription, which provides enterprise-grade AI, security, and dedicated support. This tier offers comprehensive administrative controls such as SCIM, domain verification, and role-based access. Your organization benefits from advanced data privacy through custom retention policies and encryption, with a strict guarantee that business data is never used for training. Furthermore, the plan includes 24/7 priority support, custom legal terms, and flexible invoicing with volume discounts.
How Does ChatGPT Work?
How to Access ChatGPT
ChatGPT's interface is deliberately clean and intuitive. Whether on desktop or via the official mobile app (iOS and Android), the experience mirrors a standard messaging platform. Your conversation history appears in a left-hand panel, and a "New Chat" button at the top lets you spin up a fresh session at any time.
One best practice worth following: keep one conversation per topic. If you're asking for passport renewal advice in one thread and want dinner recipe ideas, open a new chat. Mixing subjects dilutes context and degrades response quality. ChatGPT's real strength lies in its ability to refine and sharpen answers iteratively, the longer and more focused the conversation, the better the output.
Can You Use Voice Mode With ChatGPT?
Yes. Voice conversation is available on both mobile (via the app) and desktop. To activate it, open a chat and click the headphone icon in the bottom-right corner. ChatGPT will respond in your language, and on first use, it prompts you to choose from a selection of available voices.
This feature is now available to all users, including those on the free tier, a significant expansion from its previous paid-only status.
What Are GPTs, and What Are They For?
Paid subscribers gain access to custom GPTs, purpose-built variations of ChatGPT trained or configured for specific domains. Think of them as specialist modes: there are GPTs optimized for SEO writing, legal drafting, scientific explanation, coding assistance, and more. Each one fine-tunes tone, vocabulary, and output style to suit its target use case.
To use one, simply start a new chat, select the relevant GPT before launching the conversation, and proceed as usual..
What Can You Use ChatGPT For?
Correcting and Translating Text
ChatGPT is a genuinely powerful tool for proofreading and translation. Need to draft a formal email in Japanese or a professional cover letter in German? The model handles it with precision. That said, one key caveat applies: everything you enter into the chat may be used by OpenAI to improve the model. Avoid pasting sensitive data, financial documents, personal identification, confidential correspondence.
For a deeper look at what happens to your data, read our article: AI Prompts and Privacy: What You Share With ChatGPT Doesn't Just Disappear.
Travel Ideas and Recipe Suggestions
ChatGPT excels at personalized ideation. Unlike a standard search engine, it can process nuanced, multi-variable requests, maximum travel distance from your city, preferred transport method, dietary restrictions for a recipe, preferred landscape type. The output is curated and conversational, not a raw list of links.
Explaining Abstract or Difficult Concepts
Need a clear breakdown of string theory, blockchain consensus mechanisms, or the Fermi Paradox? ChatGPT handles complex conceptual explanations with precision, adjusting depth and vocabulary to your level. On paid plans, you can call on domain-specific GPTs for even more targeted explanations.
Navigating Administrative and Technical Processes
Administrative red tape, visa applications, tax filings, and permit procedures are notoriously opaque. ChatGPT can walk you through step-by-step processes in plain language, helping you understand requirements, deadlines, and what documentation you need to prepare.
Analyzing Files and Websites
With GPT-5, you can upload files directly into the chat, PDFs, Word documents, spreadsheets, and have ChatGPT analyze, summarize, or provide feedback on them. A particularly practical use case: uploading your CV for structural critique, checking which sections read clearly, and getting actionable improvement suggestions. Files can be uploaded from your local device or pulled from OneDrive or Google Drive.
Important: Do not upload documents containing sensitive personal data, pay stubs, tax returns, medical records, or anything you wouldn't want processed externally.
Web Search and Reasoning Mode
Two features deserve special mention.
Web Search enables ChatGPT to browse the internet in real time, ideal when you're looking for a specific product, local restaurant, or up-to-date information. Results can be presented as a standard list or, when relevant, displayed on an integrated map directly inside the chat window.
Reasoning Mode is designed to reduce errors. When activated, ChatGPT works through its answer before committing to it, essentially self-correcting via reinforcement learning before delivering a response. The result is measurably more reliable output on complex or ambiguous queries.
Curious about how reinforcement learning actually works? We break it down here: Supervised, Unsupervised, Reinforcement Learning: How Does AI Actually Learn?
And Much More
The use cases above are just the surface. ChatGPT can generate gift ideas, design game concepts, offer strategic advice, surface detailed information on specific figures or topics, and plenty more. With voice mode enabled, the experience starts to resemble something straight out of the 2013 film Her, a glimpse at the emerging reality of human-AI interaction.
Want to understand where all this is heading? Explore our deep dive: AI and the Future of Work: Hype vs. Reality
FAQ
What exactly is ChatGPT?
ChatGPT is a conversational AI chatbot developed by OpenAI, launched publicly in November 2022. It answers questions, provides recommendations, explains concepts, and is increasingly evolving into a full AI agent capable of connecting to external apps and executing complex, multi-step tasks.
Which versions of ChatGPT are available in 2025?
The current model lineup includes GPT-5.5 Instant, GPT-5.5 Thinking, GPT-5.5 pro and GPT-5.3, each accessible depending on your plan and usage level.
How much does ChatGPT cost?
ChatGPT offers Free, Go ($8/mo), Plus ($23/mo), and Pro ($103/mo) tiers for individuals, alongside a Business plan ($21/user/mo) and a high-security Enterprise subscription for large-scale corporate needs. These plans scale from basic access to advanced GPT-5.5 models, specialized coding tools, and rigorous data privacy compliance.
Can you talk to ChatGPT using your voice?
Yes. Voice mode is available on both the mobile app and desktop. Click the headphone icon within any chat to activate it. The feature is now open to all users, including those on the free tier.
What are the main things you can do with ChatGPT?
Core use cases include text correction and translation, personalized travel and recipe suggestions, complex concept explanation, administrative guidance, file analysis, real-time web search, and reasoning-assisted problem-solving.
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