1. History and Design Philosophy: Fossil is designed to be a distributed version control system that also includes bug tracking and wiki support, while Git is focused solely on version control with a decentralized structure.
2. Data Storage: Fossil stores all project data in a single SQLite database file, making it easier to manage and backup, while Git stores data in a distributed manner across multiple hidden folders in the project directory.
3. User Interface: Fossil provides a built-in web interface for project tracking and management, while Git relies on third-party tools or plugins for web-based functionalities.
4. Workflow Complexity: Fossil offers a simpler and more integrated workflow, making it easier for beginners to start using, while Git allows for more complex and customizable workflows, suitable for advanced users.
5. File Renaming and Moving: Fossil tracks file renaming and moving automatically without explicit commands, whereas Git requires users to explicitly mark file changes as renames or moves.
6. Branching Model: Fossil uses a timeline-based approach for branching, allowing for easy visualization of project history, while Git follows a more complex and flexible branch management system with features like rebasing and cherry-picking.

In Summary, Fossil and Git have key differences in design philosophy, data storage, user interface, workflow complexity, file tracking, and branching model that cater to different user preferences and project requirements.