depends on your native language and what other languages you speak already. If you already speak Italian, Spanish will be easier, if you already speak Dutch, German will be easier

I think that Spanish is harder than German. I started learning both of them in the same time and now I speak German as my mother tongue and I'm a teacher here, bit in Spanish I wasn't so successful

It more depends on motivation. German is classified as being more difficult for native English (Germanic Language) speakers than Spanish. However, if you have more motivation, greater interest, or some sort of connection to German or Germany . . .  you will be willing to spend more time learning it than Spanish.  

Like the others already mentioned, it depends on the languages you already speak. I see that you have a pretty high level of English, which could make German easier, but also a high level of French, which can help you with your Spanish.

It also really depends on your motivation though. German could be a lot easier for me, since I'm Dutch, but I lack the motivation to study it. Spanish is more difficult, but I enjoy that language so much, that I can spend hours studying it, reading books, watching shows, talking to natives.

Go with what you want to study most and you will succeed!

I tihink german is harder, but I'm a portuguese speaker so spanish is easier for me, because they are romance languages.