How is a unitary system of government different from federalism?

In a unitary system, there is one leader who runs the government, but in federalism, leadership is shared among several.

In a unitary system, a strong central government controls weak states, but in federalism, the central power is shared with states.

In a unitary system, there is no such thing as different forms of leadership, but in federalism, there is such a thing.

In a unitary system, a lack of central leadership allows the states to lead in most ways, but in federalism, leadership is limited.

In an unitary system, government power is very centralized. From the capital of the state, this power controls most aspects of life of the different territories that are part of said state. An example of this system in France, where the degree of autonomy of the regions is much less than for example the autonomy that U.S. states have.

A federalist system is one where the central government is weaker, and many, if not most, powers fall under the juridistiction of the administrative divisions. The United States and Germany are important examples of this type of government organization.