关于父母在美国签去欧洲旅游的签证

不好意思，移民签证改成了只有美，加，澳，新了，只好上这儿来问。

请问父母来美国探亲后，如果我们想去欧洲旅游，父母是可以在美国签证呢，还是要在来美之前在国内签好？现在欧盟对国内旅游放开，但只允许跟随旅游团。我去法国使馆的网页查了一下，上面的信息好像有点矛盾：
先说了‘Note that the applicant should apply for the visa and should obtain it in his/her country of residence before traveling’，然后又说‘A proof of resident status in the USA and its copy.( green card, valid US visa and copy of valid I-20 or valid I-AP66, visas...) if you are not a US citizen. Applications for a short stay visa from holders of B1/B2 visas in the United States are subject to a heavier and longer procedure, and the personal appearance is required.’。

请问到底来美之后再去签行不行啊？多谢了！！