My wife's reply (she's the one who took French): It is not. They are about the same difficulty, but reading and writing on TEF are much harder than TCF. The only section of TCF that might be a bit harder than TEF is listening, because you can hear the audio clip only once.
As for TCF speaking, it depends on your strengths. To me, roleplaying and convincing the examinateur was difficult, especially since you need to reply to their arguments and follow what they say. Both TEF speaking tasks are roleplaying, while only one on TCF. TCF has three speaking tasks, but the first one is always the same - present yourself. You can practice for that one. The second question (roleplay) is similar to the first TEF question. The third question is to talk about a topic without interruption, and perhaps this is the one people are scared of, but second TEF roleplay is also scary for some people (it was for me). So it's about the same. If you are going for B2, you don't need to be perfect. I made some errors and hesitated in the third question and didn't do great, but I still got B2 (and maximum points for B2, so level 8 and not 7).
My advice for everyone is to try TCF. It is simply an easier test, and it doesn't have the unpredictable writing task 1 (fait divers) which can mess up your whole score. Of course, there are people who don't have issues with TEF. It's not impossible to score well. But the fact that TCF doesn't have B2 inferior, and that at least two components of the test are much easier than TEF, made me decide to focus solely on TCF. It might also be the best course of action for someone else. (I never attempted TEF because I passed TCF on first try, but I don't regret my decision to go for TCF).