As far as I know, SFML doesn't provide own anti aliasing. Well, when you create a new window, there is an optional parameter for the anti-aliasing level. But this super-sample anti-aliasing is a default handeled by the graphics driver instead of SFML. You can easily get that with GLUT, too.
Internally, SFML doesn't use render to texture, I think. But there is a class to do so on you own. It's named
sf::RenderTarget. You can render to all classes derived from that, including
sf::RenderTexture, which might be exactly what you are looking for.
You could either do rendering yourself using raw OpenGL and handle all shaders, render targets and framebuffers yourself. Or you could make use of another SFML class provided for this case. If I remember correctly, it was called
sf::PostFX and was renamed to
sf::Shader now. Though I haven't used those classes, it seems rather easy to use them and apply effects. You read the documentation, it is a very good one which many described use cases. But since SFML has only 2D capabilities, I am not sure whether you can use that for a 3D game or not.
Nearly all recent AAA titles make use of deferred rendering, which means to render multiple attributes like depth, view space normals and texture color, to texture. Shading can be applied by reading from those textures, so that the geometry hasn't to be drawn multiple times. This is a step further than what you want to do. Deferred rendering is especially useful for computing a lot of lights.
At least for deferred rendering, anti-aliasing is still a big issue. There are various approaches with their trade-offs. But super sampling is to slow in most cases since you have to super sample all the textures rendered to, which amplified rapidly. What some games do is to detect hard edges using depth and normal information and apply a blur to those pixels. Easier implementations do only read the color texture, for example FXAA. Those are what you want to implement. That is kind of faked anti-aliasing but it has an acceptable low performance trade off.
But before you start altering you whole game think carefully if it makes sense to use those post process anti-aliasing algorithms. If you don't use deferred rendering, it is very likely that you are fine with the default super sampling. It can be used by passing
sf::ContextSettings to your