From this page you can download an example integrating Autofac and MEF via the .NET Composition Primitives.

The implementation is a ‘chat client’ built on the Codeplex drop of MEF and an early build of Autofac 2. It shows how constraints and higher-order dependencies interact.

Readers seeking a production-capable Autofac/MEF integration should download Autofac.Integration.Mef.dll via the .NET 4.0 version of Autofac.