Vicente Fox didn't mince words in a tweet on Trump's proposed border wall.

One wall - two very different characterizations.
Amid reports that Donald Trump may ask Congress and not Mexico to pay for a border wall between U.S. and Mexico, the president-elected tweeted on Friday, "The dishonest media does not report that any money spent on building the Great Wall (for sake of speed), will be paid back by Mexico later!"
Unlike Trump's vision of a "Great Wall," Vicente Fox, Mexico's former president, sees it as a "racist monument."  Fox said on Twitter, "Trump may ask whoever he wants, but still neither myself nor Mexico are going to pay for his racist monument. Another promise he can't keep."
If that wasn't clear enough, Fox followed up with another tweet, "TRUMP,  when will you understand that I am not paying for that f**ken wall. Be clear with US tax payers. They will pay for it."
So how likely is it that Trump can get Mexico to foot the bill? Not very, if you ask outgoing Secretary of State John Kerry, who said in a recent ABC News interview, "They’re not going to voluntarily pony up and pay for something they disagree with."
Even some Republicans agree with Kerry on this issue. CNN reports, "a number of Republicans suggested that Trump's claim amounted to wishful thinking, saying they believed the billionaire businessman would ultimately backtrack on one of his central campaign promises."