The French MEP who resigned his position in charge of negotiating the international Anti-Counterfeiting Trade Agreement (Acta) has said it "goes too far" by potentially cutting access to lifesaving generic drugs and restricting internet freedom.

In an exclusive interview with the Guardian, Kader Arif – a member of the European parliament's international trade group, who was the lead negotiator over Acta – said that despite talks over the agreement having begun in 2007, "the European parliament, which represents the rights of the people, had no access to this mandate, neither had it information of the position defended by the commission or the demands of the other parties to the agreement".

Arif resigned in protest on 26 January as the EU signed the treaty, saying that he wished to "denounce in the strongest manner the process that led to the signing of this agreement: no association of civil society [and] lack of transparency from the beginning".

He said that it now threatens online freedom, access to the use of generic versions of drugs for treating illnesses, and could potentially mean that someone crossing a border who has a single song or film on their computer could face criminal charges.

Asked what he thought European citizens should do, Mr Arif said: "Showing that there is interest and concern about this agreement is the best way of creating a real public debate, which was never possible until now because of the lack of transparency on this dossier. Especially if the timeframe is short, raising awareness of members of parliament will be crucial. And because Acta is a mixed agreement, it will have to be ratified both by the European parliament and by every member state of the union, so there is also an opportunity to organise debates at the national level."

He says that it is now impossible to renegotiate the agreement because the 11 key parties to it concluded their discussions on 1 October 2011: "the European commission negotiated it on behalf of the EU, on the basis of a mandate given by the member states in 2007."

That means, he says, that "at this stage one can only accept or reject the agreement – no change of the text is possible. If the right wing of the European parliament had not imposed such a tight calendar, the members of the European parliament could have drafted an interim report, which would have put conditionalities to the ratification of the agreement, by giving recommendations to the commission and member states on how to implement it. But this is no longer a feasible option."

"The title of this agreement is misleading, because it's not only about counterfeiting, it's about the violation of intellectual property rights," he told the Guardian. "There is a major difference between these two concepts."

Acta has triggered public protests in a number of European and other countries, as well as online attacks by the hacking collective Anonymous. The US, EU member states, Australia, New Zealand, Canada, Japan and a number of other countries have signed it, although none has yet ratified it in national legislation.

The agreement would create an international framework and set of standards for a voluntary legal regime to enforce intellectual property rights across national boundaries.

Arif said one example illustrates this difference particularly well – the case of generic medicines. "Generic medicines are not counterfeited medicines; they are not the fake version of a drug; they are a generic version of a drug, produced either because the patent on the original drug has expired, or because a country has to put in place public health policies," he said.

A number of countries such as India and African nations have sought to use generic versions of drugs for infections such as HIV, which has often been resisted by pharmaceutical companies. Under Acta, Arif fears such countries would not have the same freedom to determine their own actions.

"There are international agreements, such as the Trips agreement, which foresees this last possibility," he said. "They're particularly important for developing countries which cannot afford to pay for patented HIV drugs, for example.

"The problem with Acta is that, by focusing on the fight against violation of intellectual property rights in general, it treats a generic drug just as a counterfeited drug. This means the patent holder can stop the shipping of the drugs to a developing country, seize the cargo and even order the destruction of the drugs as a preventive measure."

He thinks that is a key flaw: "Acta also limits the flexibilities listed in the Trips agreements to support developing countries in need of generic drugs. When the question of finding the right equilibrium between protection of intellectual property rights and protection of final users is so crucial, Acta appears to be very unbalanced in favour of patent holders. This is one of the major problems with the agreement."

Internet freedoms could also be under threat if Acta is ratified in its present form, he says. "The chapter on internet is particularly worrying as some experts consider it reintroduces the concept of liability of internet providers, which is clearly excluded in the European legislation." That could make ISPs, who provide internet access, liable for users' illicit file-sharing.

Arif also expressed concern that there could be more intrusive checks at borders to fight counterfeiting.

"I see a great risk concerning checks at borders, and the agreement foresees criminal sanctions against people using counterfeited products as a commercial activity," he said.

"This is relevant for the trade of fake shoes or bags for example, but what about data downloaded from the internet? If a customs officer considers that you may set up a commercial activity just by having one movie or one song on your computer, which is true in theory, you could face criminal sanctions.

"I don't want people to have their laptops or MP3 players searched at borders, there needs to be a clearer distinction between normal citizens and counterfeiters which trade fake products as a commercial activity. Acta goes too far."

The text of the finalised treaty (PDF) has now been made public, and the European commission has begun to try to explain how Acta would work. It has also published a document called 10 Myths about Acta, asserting that the public was informed "since the launch of the negotiations"; that it is drafted "in very flexible terms" and that "safeguards and exceptions under EU law or under the Trips agreement remain fully preserved".

It also insists that "Acta is about tackling large-scale illegal activity … there is a provision on Acta specifically exempting travellers from checks if the infringing goods are of a non-commercial nature and not part of large-scale trafficking".