An escort agency bought a billboard on the main road into Mobile World Congress

An escort agency in Barcelona bought up one of the highly sought-after billboards on the main road from the center of the city into the Mobile World Congress venue.

And it appeared right next to one of Samsung's outdoor ads.

Escorts and prostitutes flock upon Barcelona's hotels and bars as the huge mobile trade show takes place each year as they look to take home top-price rates from wealthy business people.

That's not all, according to two Facebook users commenting on the billboard photo posted by MWC-goer Helen Keegan, the Apricots escort agency website also used the official GSMA Mobile World Congress logo on its website, with a banner-type ad stating "We are ready."

The GSMA, which organizes MWC, has now "taken action" on the unauthorized use of its logo and branding on the website, according to Facebook user Maria Shiao Di Francesco. She said she had been emailed by GSMA director general Anne Bouverot, who Di Francesco says is "determined not to let MWC become a CES under her watch." CES is the electronics trade show that takes place in Las Vegas each year. It became a hotspot for commercial sex several years ago when a porn trade show was held at the same time. The two shows' schedules have since been changed to avoid that.

However, while the GSMA may have forced the removal of its logo from the Apricots website, it is clear the agency is still very much targeting the last remaining MWC delegates. A blog post still appears on its website advising users to "be careful with taxis during the Mobile World Congress of Barcelona." It goes on to advise that taxi drivers with passengers asking to go to a brothel will often drive to a different one, which charges higher rates.

A GSMA spokeswoman told Business Insider: "We absolutely do not condone prostitution or the exploitation of women at our event. We are constantly monitoring and addressing issues as we are made aware of them. In this particular case, the company was using the Mobile World Congress logo on their website. This has now been removed. Billboards that do not specifically reference Mobile World Congress or our brand are beyond our direct control, but we are working with the city of Barcelona to address these issues in the future. We are committed as an organisation to making our event a positive environment for all attendees and will continue to focus resources to ensure this."

On Wednesday there was a small protest outside the main Fira Gran Via Mobile World Congress venue. Protesters bore signs which read: "Real men don't buy girls."

This is not the first year MWC has been plunged into controversy around the sex trade. In 2012 the GSMA kicked out and banned Russian telecoms company CBOSS from the show. The company had been handing out leaflets offering visitors "champagne, caviar and a beautiful girl" if they attended business briefings.

Prostitution in Spain is not illegal, but nor is it regulated by authorities. However, Barcelona recently introduced fines for prostitutes working and clients picking up sex workers on the street.