The French Football League's (LFP)'s Administrative Council has asked all professional clubs to move their headquarters to France so that they are subjected to the country's tax laws.
However, Monaco have so far refused to do so and have appealed against the ruling, as their foreign players currently do not have to pay any income tax.
"Next year, we will seek as usual to consolidate our position against increased competition with the arrival of a foreign club in Ligue 1," ESPN quotes Labrune as saying.
"This is not a fight. Monaco is welcome to Ligue 1, but the LFP, our position is quite simple. I say yes to AS Monaco being in Ligue 1, but they must be in compliance with our legal and ethical rules as they have been defined.
"[Marseille] must try to consolidate our place on the podium without the means of the Russians at Monaco (owned by billionaire Dmitry Rybolovlev) or the Qataris of PSG and without being able to spend madly. We will try strengthening the team gradually year on year to qualify each season for the Champions League and to become competitive on the European stage."
Marseille have secured a second-place finish in Ligue 1 this season.