USA Today published the article and they have good reliability and lean just left of center. They will have an "agenda" against Trump since he is far-right so they will publish articles against his authoritarian antics.
Other major sources like the New York Times, CNN, Time Magazine, & CBS all reported on this plan as well. It is worth mentioning that the name "Arc de Trump" is informal (CBS) and is mainly used by his detractors.
Trump's direct quote on it was: ""It's going to be really beautiful. I think it's going to be fantastic," as he held a model of the arch. "There's a rendering of what it will look like. You have three sizes." He added, "I happen to think the large one," indicating his preference. CBS News' Ed O'Keefe asked the president who the arch is for, and Mr. Trump pointed at himself: "Me."" (CBS)
According to multiple reliable sources, this is a true statement: Trump plans to build an "Arc de Trump." (BBC) . Though it is worth mentioning that there is a very long list of things Trump has planned to do that never came into reality such as arresting Hilary Clinton and building an entire wall between the USA and Mexico. And while the name "Arc de Trump" does not come from Trump or his administration, it is aptly named by his critics since he himself said it was for him.
https://www.cbsnews.com/news/trump-new-arch-resembling-arc-de-triomphe/
https://www.bbc.com/news/articles/cy7e8lv176go